The ones I can think of right now are
The Aune DAC/Amp combo <- I would go with this one
Maverick D1 <- More expensive than the Aune
Zero DAC , This one has optical input but no RCA input. Build quality seems okay at best
You will probably have to look at ebay for the above DACs / Amps.
There's more, hopefully someone else can give their input as well. I can't think of any standalone amps right now on my mind right now other than looking at the For sale section on this forum for some Meier Corda Headfive or Arietta amps.
Edited by kite7 - 8/30/10 at 3:59pm