Too much torque in the seat bolts

I just bought a used KZ750 twin and two of the three bolts meant to hold the seat to the frame have the heads completely torqued off. Anyone got any ideas how to get them out so I can get some new ones in?

Sears has a bolt remover set that works great or you can try using a dremmel to cut a couple of flat spots on the rounded off head and use vice grips if you can get to it.