Hey Nick,
You can make a form by laminating plywood to the right thickness with common wood glue or buying the stuff premade for beams,can't think what its called.(help me out somebody)
Rather than c clamps,if you plan to make only 1 set of limbs,personally I'd go with the rubber band method for clamping.
If you plan on making several sets,an air hose type form would be better IMO,either way you need a way to heat the form and limb to cure the glue,from puttin it in the car on a warm day to a fancy hotbox.
Heres how I make forms,this one is a hybrid,but you can adapt it to a TD limb fom easily.
http://www.kennyscustomarchery.com/