Maybe Audio Physic. Also, Gershman (Idol), ProAc Future series and DeVore come to mind, as well. I've heard all of those with tube amps and they sounded great.
Totem like sound for tube amplification
Any ideas on a loudspeaker that has a similar signature to Totem (Forest Signature, Hawk, Arro) that would play well with a Primaluna Dialogue Premium HP integrated?