The quick specs on the flatbed....
frame bobbed at the shackle hangers, bed frame made of 4x4 box channel, deck is 1/8" steel diamond plate. Cage is 2" schedule 40, main hoop is welded to bed. The rear hoop, spreaders and gear rack are removeable (as one peice) so that I could still carry large stuff on the bed if I needed to. The gear rack is 1" tube with expanded metal floor.
The whole thing is welded to the frame. Really stiffened things up and I loved it. Made the springs work better.
Best feature (IMO) was the spare tire mount under the bed. Removed spare tire crossmember and other forward (round) crossmember. Re-bent and welded in a new round crossmember, relocated rear shock mounts, re-used the stock spare tire winch. Allowed my to fit a 35" spare under the bed. I think that is the biggest drawback to bobbed beds and flat beds is that there's nowhere to put the spare unless you put it in the bed or on a tire carrier. I didn't see the point in using up all the bed space and didn't like the idea of a tire carrier hanging out the back after I just tried to shorten the overall length of the truck.