I thought that was a neat idea. However, the mass is greater and thus the equivalent "bohr radius" would be much smaller. Maybe the two effects cancel (or maybe this decays even faster than positronium). I'm not sure how to calculate the decay rate since the particles are composite, have color charge, and is more energic with more decay products possible. I'm curious now. Anyone know which would decay faster? Is there some kind of shortcut / handwavy back of the envelope method we can use here?