Have you looked at the Innersound amps? The good thing about the Innersound, besides the good performance from what I have heard, is the trial period and warranty. I'm partial to the McCormack DNA-2 in any configuration and they can be upgraded by SMc Audio. You do get a warranty if you get a McCormack upgrade at SMc, but I don't know if it's transferable.
There is the DNA-500 you can purchase new.
http://www.iar-80.com/
There is the DNA-500 you can purchase new.
http://www.iar-80.com/