Does and HDMI splitter cable or attachment exist? Like a headphone splitter, but you plug into HDMI and get two out of it? It's probably impossible, the more that I think about it but it's worth asking.

Ummm either I don't understand what your asking or I don't understand why you didn't see the thread like four or five down. The one labeled "HDMI Switch".

thanks sorry i didn't see that

I think he's talking about something plugging an HDMI cable in one end, and getting two HDMI connectors out (i.e. to drive two monitors). I would assume there's no reason this couldn't be done, but I'm guessing that it wouldn't work with HDCP.

I don't know about working with a home theater pc, but yes they make those too. I believe monoprice has a 4X2 switcher (handles up to four sources, directed to up to two different displays).