Goran Kropp (RIP) hauled over 200 pounds of climbing gear and food on a bike from Sweden to Mt. Everest on a trailer prior to his successful solo ascent and then returned to Sweden by bike.
I think there is going to be some practical limit around that number. I've hauled about that much on a sledge before. A couple of hundred pounds of gear becomes a large, kinetic driven mass that is unwieldy to manhandle when solo hauling.