How tall is she (and her family, if they will also be using the kitchen)? 15" uppers above a 24" base would be tight for me and I'm 5'8". Someone much taller would have difficulty using half of the counter. Someone close to 5'0" tall would be fine (and might like the extra capacity on the lowest upper shelf. She could put in 27" deep bases (or leave a 3" gap between the base and the wall) but you say the kitchen is small so that might not work either. I think I'd forego the upper lazy susan.

I think 15" uppers are a good idea. But you said the kitchen is small, yet she will have an island? Islands not a good idea in a small kitchen, though perhaps it's hard to tell what you mean. Perhaps post the layout on this forum.

Here is a recent thread about 15" uppers that might be helpful. It's about inset cabinets, but the discussion is useful for any type of cabinets:

http://ths.gardenweb.com/discussions/3658481/what-depth-cabinet-for-inset

I have 14" deep for inset and love that. 15 inch deep will work if you have adequate space between the counter and the upper cabinets- I have 22" - that leaves you lots of working space visually and practically even where the base counters are not pulled out. I have 7 inch deep open under cabinet shelves on part of my kitchen (for heavily used items) as well which do not interfere with the working space, but did leave those out around the cooktop so that I could store and easily grab the tall oils etc when cooking.

I have 15 inch deep uppers and love them. They are inset. But, I do have an island and this is where I do most prep work. I am also only 5'4". The space between my uppers and counters is 18. I wouldn't do too much more if she is shorter like I am. I remember thinking 18 looked like way too much space when the cabinets went in. I am fine with it now, but couldn't really reach into the cabinet if there was much more space.

yes I am 5'4" also- my shallow under cabinet open shelves help a lot. Those and the lower shelves hold my most used items but I can also reach the middle shelf. The deeper cabinets actually makes it a little easier to reach the contents.

Great idea about visiting Ikea to get a feel for it!

We have gone through a few houses in the last few years. Went from 13" overlay, ok. To 14" overlay, loved it. To 12" overlay, uggg. Now have 15" inset -so 14" usable inside. In the famous words of Goldilocks - these are just right.

Annie - any chance she can do 27" lowers? It's lovely to have the extra countertop. We have a similar setup, but with 18" uppers and 30" lowers. With deeper uppers, comes the opportunity for more vertical storage as well.

I was just about to suggest what oldbat says - make the lowers deeper. In our first kitchen the guy that did our countertops pulled out the lower cabs so our counter was a couple of inches deeper. I completely forgot when we redid the kitchen and regretted it ever since. I keep slamming things into the backsplash thinking I have those extra two inches - and this is 10 years later.

I'm afraid there isn't room to make the lowers deeper than they are, so it's really about the uppers. I appreciate everyone's thoughts and insights. We may end up not too far from IKEA going to a kitchen design place, so that's a great recommendation...we can stop in there and see if she likes it.