If you want to see some really well thought out belt drive bikes, go to the TiCycles website. They have the dropout issues solved very nicely. They have also built bikes with just one set of stays, no left side, so you can just lay the bike down and pull the tire and tube right off with the wheel in place, never messing with the belt tension.

If you are considering a belt drive, it is worth looking at their stuff just to see what can be done. (Re-fitting bikes is also something they do a lot of: for belts, for S&S couplers, etc.)

Ben