Would Rockbox (http://www.rockbox.org/) (alternative firmware for Archos Jukebox, iPod, iAudio) be any help? Its power management is a bit crappy, but if it's running from a car battery that's probably not such a big deal!

I've no idea whether that firmware would still be compatible with the control interface used by the Alpine, and the Rockbox FAQ doesn't tell me whether I could restore the iPod to its original firmware if it turned out not to be. (It mentions dual-booting, but I don't know if that would be good enough.)

The risk-free approach, I suppose, would be to borrow an iPod that already runs Rockbox, and test that against the Alpine. So. Are you mentioning it because you use it, or alternatively do you know somebody who does?

I've been vaguely considering investigating that, but I see the iaudio documentation is still a bit sparse and I'm not keen on being bleeding edge. Though the opportunity of playing Doom on it tempts me.