It's gonna be pretty hard to hit the form factor of the empeg for cheap. This may be a little underpowered (CPU-wise) but these are the cheapest embedded motherboards I've ever found ($238 in quantity 1). It supports PCI cards (3.3V only though hmm...) so you could get one of those DivX accerlators cards to handle the Mpeg-4 and video-out. It does have a respectable amount of bootable flash at least and a pcmcia slot for good measure.