I think some folks might be interested in this. I just finished building an aux fuel cell rack for my FJ-09 using t-slot aluminum tubing from 80/20. We use this a lot at work for industrial machines, prototyping, and the like. It is extruded aluminum tubing with t-slot channels on all four sides. Nuts slide into the t-slots for infinitely variable attachment points along the tubes. The tubing has an excellent strength-to-weight ratio, allowing you to make strong, complex structures without any welding. This rack with all hardware weighs less than five pounds, and it is rock solid. I attached it to the bike using threaded hard points on the frame for grab rails and luggage racks.