Mike,
Thanks. And yes, I think these folks have cornered the market on aluminum.
I truly don't know yet. Based on RPM's web site, 8.5x20's have shipped from the InTech factory weighing anywhere from 2980 to 3920 depending on how they were equipped. I figure that mine, with 5200 lb axles and the options I ordered, will fall somewhere in the low-to-mid level of that weight range. Here is a link to some of the aluminum trailers that RPM has sold. Most of the trailers listed in the link will have a shipping weight listed:
http://www.rpmtrailersales.com/categories/aluminum-trailers