The biggest reason you don't see larger induction ranges is that the 30" ones are already at the limit of most American electrical systems as they exist. 40-50 amp circuits are all that exist currently in most homes in a range location and most American homes only have 200 amp services. If a larger range with larger needs for power were introduced, it would for sure require rewiring as a condition of it's use. And in the typical home, 200 amps of service is already pushing the limit on usage with all of the TVs, computers, and other eletronic gadgetry that are in a modern home. (It's the same reason why you seldom see a retrofit for an electric tankless water heater.) Commercial installations that use large induction hobs typically have access to 3 phase power and MUCH larger service runs. You only have to look at the different electrical requirements between a typical 1970 home and a 2010 home to see how many more circuits are now needed. Start adding in a power hungry range that needs a 70 amp circuit, and you start talking a LOT of money to rewire the run from the pole, a new panel, and the new run for the range. It's just not economically feasable for any maker to introduce something like that at this time. Youd need a paradigm shift in new home construction to make it happen. This post was edited by GreenDesigns on Fri, May 24, 13 at 9:49

We replaced a Fisher Paykel gas cooktop with a 36" Wolf induction. It sits over a Kitchenaid wall oven. It was the only brand that would fit because it has the shallowest profile. That being said, we tend to use the second wall oven much more because it is easier to access. The 36" over the 30" oven looks fine however.

Yes, it will probably work. Today most brands design both their wall ovens and cooktops to be used in this configuration, so usually similar models will work together. Realistically, even different models will usually work, electric cooktops just aren't that deep and the only worry becomes electrical hookup for the cooktop. I used a 24" cooktop for years in a foreign country and didn't find it to be bothersome. In fact, I preferred it sometimes (in full disclosure, don't like it enough to actually replace our current range with one). Ours was similar to the Bosch 500 series and really it just eliminated the open space between pots, the purpose of which is apparently to be dripped on and annoying to clean while cooking. If you are comparing a 24" cooktop to a 30" with offset burner designs (which you want if you actually cook) you do lose one left hand stir on the back left burner. However, only left handed people actually use the left hand stir, so just FYI. If you are doing it, do not skimp on your cooktop, saving money and saving space don't go well together.

Also keep in mind that you are introducing a source of heat under the induction cooktop. Heat and electronics do not play well together. It is possible that you may shorten the life of the cooktop if you are not careful about the choice you make. This is probably why manufacturers insist upon using like products in this configuration. They may have ways to expel the heat with their own equipment. If I were designing something like this venting would be a priority in my remodel. It would probably involve small fans that had access to cool air to introduce into the cavity for the cooktop and possibly one to expel the warmer air. Preferably outside, however outside the cavity into the kitchen area is preferable than trying to cool with hot air. I believe keeping the electronics cool is key to a long useful life for appliances. Especially ones that produce heat.