Excuse me while I live vicariously through your trailer project.

Here's yet another forum to browse. Looks like lots of good info on teardrop trailers. I noticed there's even a section on converting cargo trailers:

http://www.mikenchell.com/forums/

Also, the "T@B" trailers are an idea:

http://www.tab-rv.com/

It would be great to have an Airstream, except for the high price tag. I see they have something new, called the "Basecamp":

http://www.airstream.com/products/2008-fleet/travel-trailers/basecamp/index.html

Good luck with your project!!