I can confirm that this 4x2 matrix switch
which Wryker mentioned, also works for my setup.
I have output #1 going to my 3DA-1 adapter, which then goes to TV.
I have output #2 going to my Pio 1018 AVR, which then goes to TV.
If I want to play PS3 games in 3D (720p/60), I turn both outputs on, set TV to 3DA-1 input. I still get full 7.1 audio through AVR (4x2 switch acts as a splitter in this case).
If I want to watch 3D Blu-Ray I turn on output 1 only, and set AVR to either Optical (from PS3) or COAX (from the 4x2 switch). The latter is more convenient because you don't have to go into PS3 settings and change from HDMI audio to Toslink. (although I did have to change audio from PCM to Bitstream, but this setting is easier to access - during movie playback, press triangle for the popup menu). And a plain RCA cable is cheaper than fiber, although I already had both on hand.
If you don't care for buying any of the short list of currently available blu-ray 3D
's, I found this NetBlender Demo Disc
which also works in the PS3. It has 3 short clips, the 3D effects are so-so, but hey, it's free (I burned to a BD-R cause it said it was required, but will also try DVD-R or CD-R later)
So, just to avoid confusion - this switch isn't something that magically lets you get full 7.1 HD audio from Blu-Ray 3D through a HDMI 1.3 receiver... It does however save you from plugging and unplugging HDMI cables every time you'd want to watch a blu-ray 3D on your PS3. It also gives you an additional 3 HDMI inputs. Overall, certainly worth $75.
If you already own a 3D-ready DLP, and a PS3, and a decent AVR, I would recommend getting the Mitsubishi 3D-kit and this matrix switch as it will be much cheaper than getting a new 3D native LCD (or plasma or dlp) and a new HDMI 1.4 AVR.
With DLP's, since the 3D uses a checkerboard pattern, you are only getting half the resolution, but it still looks great. Definitely on-par with anything I've demo'd at Best Buy (samsung, sony, panasonic).