Microhood over a pro range is a bad idea. They only really go up to 300-400 CFM which is fine for most ranges but for high output pro style you'll want more. Plus the high heat could wreak havoc on the microwave electronics. What range are you getting? And if you don't want to give up counter space, have you considered a microwave hood?

Burners to hood distance will vary. The higher the hood less effective it will be, though putting it too low will make cooking a pain. Generally the higher output of the cooktop and the higher powered the hood, the higher it is placed. I think 30" is a good ballpark number.

Well, I was looking at the new 30 inch Bosch Benchmark series gas range and it's accompanying microhood, I have always wanted a more pro-style range but pretty much gave up because we literally have no place to put another microwave except on the counter and we don't have a ton of counter space. Then I saw some pictures of the Dacor gas range with the Dacor microhood over it, so it seems like people are doing it. There is no difference in the BTU of the bosch, which has 5 burners, or the 4 burner Dacor. So I'm not sure why it would work for the Bosch but not for the Dacor? Or any other range with similar heat output.

Sorry, when I said "have you considered a microwave hood?" in my last post I meant "have you considered a microwave DRAWER?" Of course you've considered a microwave hood :)