I have a 15hh(ish) connemara x thoroughbred. She *looks* quite LW but actually has 8.5" of bone and takes an XW saddle even at her fittest - 17.5" long.
Id happily sit a well balanced 13-14 stone (ish) person on her ... theyd have to be well balanced though, shes too nippy to take an unbalanced rider!!!
She is a sports horse though, very nippy and quick, would make a fab polo/horseball pony i swear, turns on a six pence, jumps like a stag, and does a cracking dressage test. But, a true to type conny is a good allrounder and can do quite literally, everything!!!
I weigh about 10 stone and am 5ft8/9ish (not been measured since i was about 14ish!) and she never complains about my weight, and shes technically half tb!!!
Us recently at a dressage comp (she hadnt competed at dressage in a year and hadnt been ridden for about a month or so due to exams!)
Ive also ridden my RIs pure conny and he is much much chunkier than she is, and seems much hardier. Hes also probably a hand or so smaller though!