Logically, with induction ranges available from electrolux, sears and samsung, there should be a solution. Two considerations.
Keeping the induction unit ventilation system open enough to cool the cooktop while in use.
Isolating the induction electronics from oven heat created while using the oven at its highest output. Mineral wool board insulation good to 2000 degrees between the oven and the induction unit could increase the level of insulation supplied and do the trick. Infrared thermometer to check.
Also, the guts are rumored to be supplied to Whirlpool by Bosch and they sell a 24" induction range in the UK.

Here is a link that might be useful: Roxul mineral wool rigid board insulation

I feel for you!

If your cooktop isn't returnable, this won't be of help, but if it might be, you could switch brands.

I had heard that you couldn't install a wall oven underneath induction but I just found out on Fri, you can install an oven under a Miele induction range. I called them to verify this. They told me an oven could be installed 4.5 inches below the cooktop, which is 2 9/16 inches

I hope you get this solved. How stressful.

NOTE: When posting a question about an appliance, try to include the brand, type of appliance and model number.

You should first rely on the cautions and installation instructions that came packed with your cooktop or were printed on the its carton. Same goes for the oven.

Sometimes the internet site caveat you found is an interim or obsolete warning put there because a company hasn't finished testing your type of configuration on its own products. Unfortunately, in some other cases they have done the tests, found problems and issued a "fatwa". When the cooktop and oven are from two different makers there is even more opportunity for dispute and refusal to honor warranties.

Some ovens also vent so much heat from their front that a person trying to use the cooktop has a good chance of "meltdown" as well.

Model numbers, please.

"What will happen?" The Earth will spin off its axis into the Sun. Sorry about this.

"Will I burn the house down?" No.

"Will the induction fail?" Maybe. More than likely it will shut down when it gets hot, if it gets hot.

"Will I invalidate the warranty?" Normally, with most vendors, the act of installation invalidates the warranty. But the answer is "probably yes". But you won't know until you need it.

"Is there a modification that I can make to make this work?" Yes, most likely. The issue with the induction unit is ventilation of the electronics. The unit has an internal fan. You have to make sure that air can circulate around the unit into and outof the fan and any air slots. Some vendors recommend extra ventilation holes/slots at the back of the cabinet under the countertop, or around the sides so that air flows freely inside the cabinet. There also could be a physical clearance issue since many ovens take up a lot of space for the control box at the top. This could interfere with the bottom of the cooktop, but it depends on the dimensions.

Sorry about the lack of model numbers. Here they are: Kitchenaid KICU568BL
induction cooktop. Electrolux wall oven EW30EW55GB.

Thanks everyone, for your advice. I'm still shaking but hopeful from your comments that there can be a fix. As far as spinning into the Sun, yes, I'm trying to keep perspective, things could be worse!

If all that happens is the cooktop shuts down when the oven is too hot, then I've gotten off lightly.

I remember reading somewhere that you shouldn't use the induction cooktop when you have the self clean cycle operating on the oven. I'm pretty sure that applied even for approved configurations.

Hoping you can resolve this dilemma...

As numbersjunkie said, I was also told by Miele not to use the self cleaning feature when induction is in use.

Electrolux sell an induction unit that sits in a "frame". This is what I have. I also have an electrolux oven(wavetouch or whatever) underneith.
Electrolux has "fans" in it for cooling and thus the reason for the frame it's installed in.
If you need model numbers, let me know.

LIP2000

So, you're putting a 30" oven under a 36" cooktop? Are you using a 30" cabinet, or 36"? If a 30", are you knotching out the cabinet to fit the cooktop?

Anyway, from looking at the installation guides, the heat shield may be a problem. Do you have the oven out of the box? How deep does the control panel section go back on the oven? Will it touch the shield? If so, I would not put it on, ie remove it.

It looks to me like the KA induction cooktop ventilates through the bottom front. If so, does this get covered up by the oven control section? Or is there a gap of a few inches?

I would give this a good hard look. The (partial) solution may be to let your oven installer, or cabinet guy, or GC cut some ventilation holes in the cabinet prior to installing the oven (depends on what is on either side, and on what air gap is behind the cabinet). Some 1"-2" holes along the bottom sides, rear and top (underneath the countertop) would provide cooling air.

Wow, weedmeister, you and others have really put some time and thought into my problem, and I am so grateful.

The update, not much yet I'm afraid, but I think it's going to come down to either a swap for a GE (a bit small for our existing cutout) the Electrolux (not available till April 18th) or go with our Kitchenaid. Their customer service was horrible, I'm not allowed to speak to technical support, I have to have a certified tech make the call for me.

In any case, I think we're leaning towards implementing weedmeister's suggestions. In answer to your questions, we have a 36 in cab, the heat shield is a problem in that it will touch the installed oven, but there will be about 4 inches either side of the oven in which that heated air - if that grill thing is a vent, can circulate down and out. We're also thinking of using Dan's suggestion of mineral wool board to keep the oven heat from radiating - my contractor is thinking of doing the same thing in his set-up because the self-clean function makes his cooktop go crazy too. In addition, we'll install a vent in the outside wall, perhaps we can find one that will activate with a difference in heat?? Perhaps knock a hole in the cabinet wall too.

Fyi, Bosch, who I think makes the KitchenAid components, told me first you could install an oven under their unit, then when I rang back for something else, said in fact it wouldn't work, because of the size of the junction box... not the ventilation!

I despair, how to get decent information? Also my Sears salesman said he'd had no idea of the cooktop/oven conflict. So much for manufacturer's policy of referring you to your dealer!

Thanks again, folks.

You have to make sure that air can circulate around the unit into and out of the fan and any air slots. Well, Some vendors recommend extra ventilation holes/slots at the back of the cabinet under the counter top, or around the sides so that air flows freely inside the cabinet.

Here is a link that might be useful: Appliance Repair in Los Angeles

Those bottom slots may be inlets, not outlets. One way to tell would be to plug it in and observe. It's already installed, right? Did you notice any other openings around the edges? Usually that 'shield' is there to keep the warm exhaust air from mixing with the cooler inlet air. So there may be other vent holes somewhere else.

I think both GE and Electrolux print on their units which of their cooktops are compatable. I also think this is a physical compatability issue (they don't touch) more than anything else.

Well, Kitchenaid finally got back to me and said it is just an issue of physical compatability. They say the oven won't fit. It will but I might have to bend the shield a bit. However, if I install the oven it will void the Kitchenaid warranty - which is five years on the major components.

So, I'm going to try to return it to Sears, who are so far being sympathetic but we'll see what happens when I ask them to give me my money back. Miele seems to be very straightforward with the installment, just 4 1/2 inches clearance from the top of the cooktop and they don't care what oven they're put over so long as it has a self-cooling fan. But their cut-out sizes differ, do I have to get the granite guy out again to re-cut? I'm really tired of this..