Yes, but it's not 'true' surround from DPL.
I still can't see what I am supposed to be looking for in receiver specs to ensure that it will produce real surround sound in OS X. The guy at IMG was incredibly helpful, but I still came away not being sure what to look for.
Unfortunately, I don't know much about OSX and unencoded audio in games.
This is my conclusion so far in Windows:
(a) Analogue outputs: found on most PCs, most cheap PC surround sound speakers have these eight (or 6) RCA type connectors. Some AV recievers (including my Denon AVR1910) actually have these connections as well.
(b) Digital outputs: Single cable solutions require an encoder, otherwise the reciver will just output them as stereo. Only way for that is to get a soundcard with an encoder such as Dolby Digital Live. As you say, you can fudge stereo into surround sound using Pro Logic etc so perhaps some games export stereo which is adjusted so DPL works better. This may make sense in some games that have no sound output options but again, this in in Windows which has underlying audio engine (forgot its name Direct Sound?)
Here's the back of a Denon AVR1910
The "EXT in" connections I would use if I used the analogue connections. No encoder nessecary. I read on here that some Mac Users found that certain USB soundcards work in OSX. The AV reciever should output surround sound but it won't display DD or DTS since they are encoded wheras the 7 individual analogue inputs are not.
I use the optical on the back and it works very well in conjuction with a X-Fi titanium soundcard (PCI-E) with Dolby Digital Live. There may be newer cards with Master Audio encoders that can output via HDMI.
My PC 5870 has HDMI and in theory, my soundcard can encode the sound but export via HDMI via GPU. I have not tried this though.
Basically, my conclusion with regard to surround sound, is that one can't get genuine surround sound through a single cable (optical or HDMI) without an encoder. To my knowledge, there are none for OSX unless software like JackOSX works.
So you need:
(a) An AV reciver with optic/HDMI input and a soundcard that can encode via optic or HDMI
(b) An AV reciever with seven analgoue inputs like the one above and an analogue sound card