Well if you're not set entirely on tubes... how 'bout John Atkinson's new reference: the Parasound Halo JC2? Designed by John Curl and Bob Crump of CTC Blowtorch fame. John loved the "silky highs" when driving a Boulder 860 and mentions it's better mated with warmer amps.
http://www.parasound.com/pdfs/JC2StereophileReview.pdf
http://www.parasound.com/pdfs/JC2StereophileReview.pdf