I play through a Tonelab LE and I have to say I'm quite happy with the tones I'm getting from it. For practice, I plug it into a Crate 15w amp with decent results. Sounds better than it may seem. However, I was thinking of upgrading to more serious gear. The separate preamp/poweramp combination seems more versatile to me.

Specifically, I was considering a Rocktron Velocity 100 poweramp + a Harley Benton G212 (2x12 cab with V30s).

Would this be a worthy upgrade? Would the three (Tonelab/Rocktron/2.12 cab) be compatible?
Dear God, do you actually answer prayers?

Yes, but only in a way indistinguishable from random luck or the result of your own efforts.