I used a Max Burton as a trial to see if I liked induction. It worked well. Just beware that not the entire large burner outline is heating the pan. Only the smaller one. The model I got lets you set a temperature and it would maintain it and that worked quite well. It was about $70US on amazon if I recall. You won't get a quick boil on a large pot as it is only 110.

Are you planning a real induction cooktop for the real kitchen? If so, you can set it on blocks in your temp kitchen space allowing airflow to its fan and run a suitable wire gauge conductor cable to your nearest electrical box having space for a dual breaker, or repurpose the space being used by an existing dual breaker providing power to some lower priority appliance.

The type of cooking performed should be appropriate to the ventilation available or to the anticipated pleasure in repainting the space if ventilation is inadequate.

I am doing an induction cooktop but my temp space would work better with something smaller - figuring I try a single burner plus grill, crockpot, toaster oven etc. I might actually want 2 burners but was thinking 2 separate singles could be handy later for keeping things warm at parties/holidays or other things. Although i saw a nice looking 2 burner induction. But we will mostly grill - need burner for eggs and a few other things that don't work well on the grill.

A word about your electrical power for your temp kitchen.

You are going to run your portable induction cooker(s) (PIC) on standard 120v outlets, right? I would say not to bother with a double-burner 120v induction units. You will find them all pretty seriously underpowered (you've got two burners sharing power that a single burner will use for itself.) If you get two separate PICs, though, you will need two separate circuits to run them at the same time. (We are not talking separate outlets -- we are talking separate circuits each with its own circuit breaker back at your electrical panel.) That is because many single burner PICs can draw the max amperage of a standard 120v 15 A household circuit. Run them at or above midrange power at the same time on the same circuit and you will trigger the circuit breaker. Same thing with a microwave, too. Want to run a MW and a PIC at the same time? You'll also need to figure out how to run them from separate circuits if you want to run, say, a 1000 watt MW alongside a PCI which may be pulling over a 1000 watts even when run on lower power settings. Two PICs and the MW, all run simultaneously? You will need access to 3 separate circuits. If using extension cords, be sure to get the really heavy duty ones (like for power tools). At least 12 gauge wire in them.

I like Kas's idea of getting your full size induction cooktop now and using it except for one thing: does the room for your temp kitchen have or can you easily run a 240v circuit? Depending on your cooktop, you will need a 40 amp or 50 amp circuit for it.

Later re-purposing the PIC(s) for parties and holiday gatherings

Your idea of using a PIC or two for "or keeping things warm at parties/holidays or other things" can be a good one provided you plan on leaving them in the kitchen and are not hoping they will function as silent buffet warmers. The less expensive PICs have cooling fans (like desktop and tower computers only louder) plus they can and do make a variety of electronic noises, sometimes sounding rather like tuning an antique tube radio. Maybe okay in the kitchen, but not great at the dining room table or buffet table.

Which PIC(s) to consider buying

As for which model PIC (or PICs) to get, I can second Kim G's suggestion of the Max Burton units with some caveats as discussed in this long thread from several years ago. You might want to read through it if you have not already seen it.

Also, if you have not already seen the blog at Centurylife.org on"How to choose a portable induction cooker," you may find it helpful. He recommends a Duxtop 9600LS which is similar to the current Max Burton 6400 model. While the Duxtop used to be priced at $120 like the Max Burton, it now seems to be a better buy at the current pricing of $70 to $80.

There also is a Sweethome/Wirecutter blog on the same subject with a slightly different perspective. Also covers some of the dual burner units. You can find that blog here.