There are a couple of Modwright KWA100-SE's for sale on Agon right now for around $2900. That is an incredible amp, and would match very well with your tube pre-amp as well as Vandersteens. Designer-owner Dan Wright is a big advocate of pairing Tube pre-amps with high quality SS amps, and designs accordingly. Check out this 6Moons Audio review, and good luck!
http://www.6moons.com/audioreviews/modwright6/kwa100.html
http://www.6moons.com/audioreviews/modwright6/kwa100.html