You should check local code, but I think 400cfm is the limit for no MUA required. Mine is 390cfm, budget model, but it's the first vented hood I've ever used and I love it!

You can also post questions on the Appliances forum.

Oh, meant to add that I, too, was remodeling a space that had only 30" or so available above my 30" range. Not ideal but it works.

You're not going to get much love here at GW for OTR micro-hoods. And I doubt you'll find one that will meet your criteria for as "quiet as possible". They tend to be much noisier than separate hoods.

Thanks, MG and FC. I know there isn't a lot of love for micro-hoods. I don't have much experience with any other kind, though. I posted this again on the Appliance Forum so hopefully someone will have some suggestions for me. MG, thanks for sharing that your 390cfm hood is working better for you than what you had previously. I would like an additional oven and I do have a small space, but I'd like good venting more.

Since you say you have a very tight house do you have any other combustion appliances? If so you will need make up air. There is a lot of discussion on greenbuildingadvisor.com

Good luck there is a lot of reading to do on there.

ETA: On e you get through the hoop of make up air you will need to determine which system to get, where to put it, and if the air needs to be heated based on your climate.