I have two integrated SETs, an Elekit with the Lundhal transformers and a Sophia MC-300A driving AG Trios. Both are excellent, musical amplifiers. You can get a superb sounding SET for about half of what you have available to spend. The Elekit sells for about $2500 and the Sophia about $3000 on the used market.
Integrated SET...
I recently replaced my Wilson Watt Puppy 8's with Zu Audio Omen Def Supreme. MUCH more efficient speakers, which leads me to a long time itch to try a single ended tube amp. This is the first time I've had speakers that could actually work with low power.
So, what do you recommend in terms of a good SET, preferably integrated and remote (at least for volume)? Budget is pretty flexible, but I would like to stay under $5-6k used