They decided to tear the closet out and move the refrigerator. This allowed plenty of space to move the cooktop from the island to the perimeter. We centered a custom wood hood between two equal size cabinets and added depth to the island. The homeowner also decided on double ovens so we made room for the microwave in the base cabinet of the island.
There are tons of choices when it comes to choosing a microwave from microwave/rangehood units, countertop microwaves, microwave drawers, and built in units. This unit is a countertop microwave. If you don't want your microwave on you counter, I highly recommend going this route. The interior of the cabinet is finished and replacing the microwave when it dies will be much easier than replacing a built-in unit. There are also trim kits available with some countertop units now to be used in this instance. And there are also trim kits available for purchase after market if you can find the right size to give your microwave a more built in look.