I'm building a workbench this summer, roughly in a Roubo style following Christopher Schwarz's "Workbenches" book. That involves laminating lots of Southern Yellow Pine into a massive slab for the top and big slabs for the legs. Chris recommends a clamp every six inches plus some across the edges to hold everything in place. I haven't got nearly that many clamps, or the money to buy decent ones. None of the local rental places rent anything appropriate.

Are there any tricks for working without clamps?

I could wrap a set of boards in layers of tightly stretched bicycle inner tubes. I might be able to work something out with frames made of 2x4s and wedges. Or maybe I could do something with rope.

Any good ideas?