You might consider looking at some of the offerings from Rogue Audio. I've read 2 lengthy interviews with Mark O'Brian, the owner of Rogue who says they've had a long successful relationship with Vandersteen.
When asked why, Mr. O'Brian remarked, "Because Vandersteen's don't really do anything wrong"
Currently I'm running my Sig 2's with a Rogue Cronus Magnum. After a bit of tube rolling, I've found the sound I've been looking for. Couldn't be happier.