Matt,
The solar hot air panels are home built design and integrated right into the house. The back of the collectors are actually the outside wall of the house so the profile on the panels is quite shallow at only 3.5" deep. with only 2.5" protruding above the surrounding vinyl siding.
you should be able to find a lot of info on
www.builditsolar.com Gary has a lot of interesting stuff there.
PS. I should have said that the panels produce about 45% of our daily required heat on a sunny day
Carl