there was a BR LT up near Powassan on Kijiji a few months ago (long gone now), it was a little rough but I think $1200, but yeah, pretty hard to come by
that would be a cool project, it's a long shot, but I'll let you know if I come across a skid frame and track from an LT
I met some trappers in the bush, they owned 3 BR LTs, he mentioned that since he put a 1" or 1.25" track on his, deep snow performance is significantly better
3 cottage buddies have older Tundra 250 LTs, very cool sleds but, they are heavier than the BR, they often have mechanical trouble and the steel tunnels rust