MizzouScotsman , a vendor that I have purchased sporran straps from does offer larger sizes .

They are offered in black or brown . Here are the links , hope this helps .

http://www.scottishtradingcompany.co...roducts_id=138

http://www.scottishtradingcompany.co...roducts_id=141

I am a medium build , however , I have noticed the leather sporran straps do help on the bouncing , no matter one's size .

Best , Mike