I don't know if you were even considering any hybrid amps, but as they've already been mentioned, what would be nice to see in the marketplace was one with utmost flexibility as to what tubes could be used. Just as the Primaluna's accept everything from EL34s to KT150s, and can be used in both triode and ultralinear mode--having those options in a hybrid design, using the minimum number of tubes (single-ended?), capable of driving low/varied impedance speakers (a full 50-100 watts from 4-16 ohms) would be a must audition! I'm imaging an OTL-like sound that could be enjoyed without compatibility worries. A bridgeable/mono design much preferred--in fact I just ordered a STA9 as an interim (possibly upgrade?) amp in part due to that very flexibility.
P.S. I suppose I should also mention that in a discussion on Agon, folks are wishing for even higher switching frequencies. (I don't really understand the technology. myself)