You might want to try contacting Emilio DeSoto and DeSoto sports. He makes gear for triathletes, but is known to make special requests for folks.

DeSoto makes arm coolers and coolwings, perhaps Emilio could make you a set of leg coolers?

http://desotosport.com/products/prod...ry=Accessories

Seems like it'd be pretty easy to size up the arm coolers in girth and length.