There are so many microwave brands out there - and most of them have largely the same features. They all have the carousel rotating in the horizontal plane.
What if we have a microwave with carousel rotating in the vertical plane, like we see in a tumble dryer? The magnetron would be on the bottom
pointing upwards, and not positioned to the side as with most microwaves.
The vertical rotation carousel would then not only move the food around, as with a regular horizontal carousel, but it would tumble it, thus exposing more surfaces as compared to the regular horizontal carousel.
Moreover, if we make part of the rotating drum transparent to microwaves and part of it able to absorb microwaves for conventional heating, then we can peform combination cooking with both microwaving and stir-frying simultaneously.
Whereas regular stir-fry cooking tends to cook the food surface first via hot surface contact, the microwaves tend to penetrate more deeply. Thus with the combination method we might be able to cut down on cooking time, by more quickly delivering more energy into the food by these dual methods.
EDIT: this is literally half-bakery in the most literal sense of the phrase