Yes and No
As far as I'm aware both 2010 and 2011 Mac Mini's support 5.1 channel reproduction via either HDMI or Digital out via sound output port if correct cable used - the discrete graphic chip in higher model is supposed to support DTS HD and other sources.
However, why the worry, as long as you are connected to reasonable WLAN or LAN you can stream to most wireless equipped devices be they LCD TV,s AV Receivers or HTC's - in my case I have both an LG HTC and Xbox 360 and my Mac Mini streams effortlessly to these - depending on file used, I get original sound reproduction - a few MKV's cause issues with both Xbox and HTC - however, that's my fault for downloading incorrect HD content - further, I have actually connected Mac Mini Audio out with Digital cable to input into HTC directly - however, not an ideal solution as your lose upscaling capability by swathing source material on my HTC, higher quality AV receivers do not suffer this problem - another option would be a new sound bar - great if you can pick-one up cheap.
