There's not many options out there for a small avr to just run a few channels or for those that aren't interested in all the new surround formats.
Z
I was thinking I could help you with some more options, but none of the three other slim AVR's I know of (Pioneer, Integra, and Yamaha) have pre-outs to support external amplifiers!
The Marantz slim AVR's only have Pre-outs for L & R, but that is why I got mine and it works fine set up the way you are describing. The limitation to Audyssey XT (not 32) is a notable shortfall (although XT is about right for the MSRP).
Also, mine had an HDMI problem at about 10 months. Warranty covered it, but it spent 1.5 weeks in shop!
After that, I put a fan on top to ensure better air circulation.