the reason you can have two drum kits in G-1000 because it has two midi ports (32 channels).
on an XG (yamaha) instruments, you can have as many drumkits as you want, even on a single MIDI port.

I must say that the best guitar effects are on the Roland Sound Canvas modules (G800/G1000) SC880...

I think the new VA7 uses the same engine as SC8850.