After watching the TM construction video several times, I am thinking that the only "Frame" in the sidewall of the roof is the outer perimeter. There appears to be an aluminum plate right at the hinge area. Other than that, I think that I may be able to cut a hole any size that I want without interference. I'm going to take a trip to Anaheim and talk to the guys at Custom RV to see what they think.
I'm thinking a solid (non-opening) window (single pane on 2nd thought) to keep the weight down and increase the strength.
http://www.trailmanor.com/WebDocs/Media/index08.html