[Cory]

You could try 80/20. They make 1"x1" 1"x2" 2"x2" and many other sizes. We used the 1"x1" last year and are using it again this year, and have found it to be strong enough for our needs. It is actually lighter than comparably sized aluminum tube, until you add the fasteners. This year we welded the frame and saved nearly 20 lbs from not using fasteners. T-nuts and fasteners do add up, both in weight and cost, however.

Cory