Still Not Practical
I have finally found at least a remotely justifiable reason to get one of these:
With new DVD players having USB capabilities, you could actually use a Gumstix to provide a USB bridge to a shared network drive full of DivX movies or the like. It would effectively be a LAN bridge for your DVD player, without the DVD player having to support such a thing.
There are better ways to do this, but this way would be fun.