I have seen that before and I think it was even posted before. I don't know if it would actually work with our wheels.
There was one can mount that actually strapped to the tire it's self. It actually looked pretty sturdy. It was also a more universal mount so you could use a number of cans. I'll see if I can find it again.
That one huge bolt is larger than most hinges on rear tire carriers though. I think it could take the strain, especially since the gate stays closed most of the time, the weight is distributed on both sides at that point.