Alex,
I'm in exactly the same boat. Well, I don't have an Alpine - mine is a Kenwood LCD monitor (which gives me the additional fun of having two devices reacting to the same remote ), but that's the only difference. So, yes, I'd like to join you building something to make some empeg output appear on the LCD through the video in. The BOB-II you mentioned seems like a very good starting point. I'm an electronics engineer, but I really only worked on the software side of projects (but very close to hardware there), so as you said: your hardware know-how, my software know-how!
While I have your attention, and as you seem to know about hardware products, let me ask you about another idea I had. The empeg's StrongARM integrates a standard LCD interface, IIRC, and it's used in the empeg. So, if we could somehow get access to this interface, then all we'd need is some sort-of-standard LCD-to-Video-converter. Does such a thing exist? If so, and if we could find a way to connect it internlly, then it'd be really easy to get the empeg output (including visuals!) on our LCDs... . So again, does such an LCD-to-Video converter exist?

Daniel