I am doing this but with a reverse config.. A 36" induction and a 12" gas wok top. The advice from my countertop place was to have a cabinet stile under the gap between the 2 units to support that narrow piece of soapstone. This may be specific to soapstone as there is no plywood underneath it unlike the granite. So my cabinet config is 2 drawer stacks about 37" wide. The cooking area spans these two stacks.. Induction on the right and gas woktop on the left. Another consideration what brands of induction and gas units you buy and what the recommendation for clearance under the units are. If they are different recommendations, that may factorinto your cabinet planning. I would also recommend a 220 v induction as they way infinitely more powerful and I find do not buzz as much. Look at eBay and Craigslist. I often see a single unit from Miele or Wolf or Gaggenau for a couple hundred bucks. The electrical is not a big deal. That being said, I am managing for 2+yr remodel on a single Max Burton induction from Amazon and it is so wonderful and really changed my mind to do main cooktop as induction.

Thanks for your input! Actually the electric IS a big deal since there is no way of bringing a 240 line since we are on a slab. It would require pulling up the floor and trenching into the concrete. It's not a complete kitchen renovation, only the island. So the Max Burtn is decent?