After pondering the solution a bit more, I changed the path I was going to take and instead did the following;
Hook Xbox 360, PS3, and DirectTV receiver into TV (KDL55NNX810) with HDMI 1.3 cables (so all should be able to pass 3d video).
Hook TV to receiver (Sony HT-SS360) with digital optical audio to pass audio to receiver.
When using the Xbox, my receiver indicates that I'm getting 5.1 channel sound, and I've verified this by listening to each speaker individually.
However, when I use the PS3, for 3D BD playback (Bolt, in this case), the receiver indicates that I'm only getting 2 channel audio, which I have verified. I've manually configured the audio outputs on the PS3's audio settings to ensure I'm outputting 5.1, and hitting 'info' during the 3d BD playback indicates that Dolby 5.1 is the audio track being played. I have not tested the DirectTV reciever.
So how do I get my BD's to play with 5.1 audio through the PS3, and why won't the PS3 output 5.1 audio if the Xbox 360 will?
Ok, so I recently obtained a new Sony Bravia KDL55NX810 for next to nothing (horray!). As of yesterday, I picked up the 3d starter package on buy.com on sale.