I have drilled two 10g's, one 30g and *ahem* attempted to drill a 55g (that didn't work out so good, lol). All my successful drillings have been on the backs of the tanks. I imploded the 55g when attempting to drill the end. I have also drilled a 40 breeder, 110 shallow reef, a 72custom and a 75g. The 55g is the only one that didn't work out.

Drilling a 10 requires a real light touch, that glass is so thin that if you put too much pressure on the drill, you don't have a tank anymore.