There is one other (and cheaper) way of enabling DVD playback on these machines - I have no idea if it would help with AVI files from the HD though.

There's a PC Card (PCMCIA/Cardbus) for the card slot which contains a hardware DVD decoder. It was made originally for the Wallstreet; I've read that it works in the Lombard, but no idea about the Pismo. IIRC, it requires a Zoomed Video enabled card slot, and I'm not sure whether the Pismo dropped that feature or not.

I've also forgotten what they're called. :?: