It's not the video bandwidth I'm worried about (yet), it's whether or not it can handle audio over HDMI. This is a relatively old splitter. I seem to remember some people having issues with it in that regard. It wasn't an issue for me, because I was using it to get video to other rooms (which weren't HDMI audio capable anyway). Now that I'm considering repurposing it, I'll have to check and see what it can do.
But if this trick DOES work, then it, combined with a switch upstream of the Mits adapter, could be used to connect both the DirecTV DVR and the PS3 to the Mits adapter, upstream of the receiver (a little cheaper than getting an HDMI detective).