Make a fiberglass pan its actually very easy if a beautiful finish isn't required. 1/2-3/4" underlayment plywood, fiberglass mat and woving, MAS - West Systems or another marine grade epoxy. epoxy the plywood form then start laying fiberglass and wetting it out with epoxy. finish with a gel coat. West Systems sells a venturi generator ( 885 Vacuum Bagging Kit )$175.00 on amazon for compressors to vacuum bag, that makes it really nice. tell me how big of an area i WILL FIGURE THE MATERIALS AND COST FOR YOU. IF YOU HAVE A DECENT CFM AIR COMPRESSOR THAT VENTURI CAN MAKE FABRICATING VERY EASY IF FIBERGLASS, CARBON FIBER, KEVLAR OR OTHER COMPOSITES CAN BE USED. MY prosthetic leg socket is carbon fiber and fiberglass and strong as a moe foe, plus it looks cool. Theres a guy me sells good epoxy for around $40-$45 gal half the cost of west systems