Some will say tube on top and strong solid on bottom to biamp.
I'll be interested in your findings, because I honestly don't believe the realism we heard in Denver can be duplicated with tubes on top. The shimmer and sheen, attack and decay, etc., etc., of cymbals, triangles and the like was just about spot on IMHO, and I have to wonder what there is to be gained by using tubes in this instance.
It's a killer recipe with most speakers, but the new Mundorf-based crossovers make things so real... I don't know, Rod. Be sure to let us know what you find out.
I'm gonna start with my current DNA-500 driving the Rev's, a DNA-1 driving the center Continuum and a DNA-125 driving the surround Continuums. I've got my classic Krell KSA-100 gold badge that might like a spin, too. 
I'd say you're pretty well set, my friend.
Personally, I believe Hugh Dean of AKSA, has proven solid state can sound as good or better than valves. And solid state is much more reliable. Even died in the wool valve guys that post on Hugh's forum, who still believe valves sound better, say for just about everyone, the reliability of solid state, dips the scales in its favour.
I
still lament the fact that Hugh didn't show for our get-together in Denver. If they're all folks say, I'd likely have ordered 4 of his amps to facilitate bi-amping the Revs.
A used Belles Ref 350A amp will fall into your price range and should sound quite nice with the SP Tech speakers.
They should, and as you know, I've heard them sound fantastic with Bob's speakers. However, I was taken aback by how his new amps sounded with the small Usher with the Beryllium tweeter.
I was seriously impressed by the little speaker in the Usher room, but the sound in Dave's room was atrocious. I don't know if it was a synergy thing or if the new design is lacking, but something was definitely amiss IMHO.
The Odyssey Mono Extremes might be nice, but for those getting speakers with the new Mundorf crossovers, I recommend getting as neutral an amp as possible. The Mono Extremes are excellent amplifiers, but they lean just a bit to the warm side IMHO, and the SP Techs require no assistance in that area. Look for something as clean, neutral and powerful as possible to reap the full benefits of the design, with the primary emphasis being "clean" and "neutral."
Extra power should be considered icing on the cake.
Apparently, in spite of dismissive attitudes on the part of some, a Crown Macro Reference works very well. Even Karsten thinks they are good!
An excellent choice for the extremely budget-conscious.
However, rumor is the Spectron bested the Crown by a *LOT* straight out of the box, so I believe it's the better choice if funds permit.
