So, with a class C as you say.. and a bunkhouse.. I find almost all C's have an overhead bed, and a main bedroom at the back. Are you thinking bunkhouse is the over the cab bed?
Certainly, as others have said, when you get into 29+ feet you move into Super C category if you want to have a heavy solid unit, and you can go up in GVW into the 550 and Kodiak style and chassis. Once there, you can have your levelers and other nice things and go to even bigger lengths.
I cannot imagine crank out windows anymore.. double pane sliders and you ventilate through the ceiling fans if need be.
I do wonder whether you are looking at smaller Class A units though?