Yes. Many ovens can do this. Ge, Miele, Bosch and others. All are relatively small, sized more like a larger MW than full size 30" wall oven.

All the ovens that use them together, AFAIK, also let you use them separately. Some are "convection microwaves", which may not have a combined mode, and only have a convection cooking mode when using as a plain oven (i.e., baking/roasting only, using hot, circulating air). Speed ovens use combined MW and convection heating to cook faster. Some speed ovens have broiler elements and more cooking modes than just convection, like a real oven. TurboChef, the original residential speed oven, IIRC, is even more like a regular oven combined with microwave, but very pricy, they've been bought out, and no one seems to be talking about them anymore.

KitchenAid also makes a dual oven where the upper oven is exactly as plllog describes. I have that unit. I can't speak for other brands, but as plllog said, the oven is smaller than the other oven, is a full functioning convection oven where you can bake pies, bread and casseroles; what ever. It is also a full functioning microwave.

I consider that it has two negatives. The inside is stainless steel and is far harder to clean than plastic. More important is that one often could use a microwave while the oven is heated or still hot, or in use. So speaking of clutter, I therefore keep an active old microwave in the garage. Also speaking of clutter: I suppose some of these special micro-convection ovens are counter units. Mine is built in and 220 volts. I would guess that a counter top unit would not compare favorably.

I have a Miele Speed oven. This oven was quite expensive. It is also a 240V wired in model, not a plug in Microwave oven that Americans are used to using. This oven does NOT have a rotating base. This is a 24 inch oven that fits a jelly roll pan and bakes 2 pans of cookies evenly and beautifully.

When I bake cookies, I preheat the oven first. If I forgot to soften the butter, I switch the oven to microwave, soften the butter, then back to preheat. As long as it it empty, I don't see why you can't use the microwave oven when it is hot.

There is a broiler element on the top. I do not broil in this oven since I haven an infrared broiler in my range.

I put this oven in the kitchen because I wanted second oven in addition to the oven that is on my range. I am very happy with my decision. Our cousin in Germany ONLY has this oven. No other microwave oven or second oven etc. She has a very large expensive house by German standard, prob about 3000 sq ft that she had extensively remodeled. She manages just fine with one oven!

I do not really use the combination modes. I don't really roast much. I generally use the rotisserie instead of roasting.

The American microwave/convection ovens have rotating bases. I have one of these on our boat. It is a 120V oven. I did not have the option of having a 240V in the boat.