I don't have a large format but I do have a torn ligament in one of my shoulders that limits how much I can carry. I've been looking at Pet Strollers, they have frames similar to Baby Strollers run less money and most of the pet baskets are easily removable. eBay has the best prices that I've found so far.
Right now I'm torn between this basket on top version, it would be nice to have a handy place to drop notes, lenses, filters etc.... http://tinyurl.com/69hrs9
and this 3 wheel jogger style with big wheels, (but not in pink)