i made a product review of the 'Optimus X', its a 2.4" MP4 player that can play avi files (in xvid format). This and those like it are by far better players than those that play AMV files.
The video quality is just as good and (if you make the file on HQ) better than those that you can play on a iPod Video.
watch below:
http://www.youtube.com/watch?v=zRts7GyLZXU
BTW the TV show that is shown on the clip was originally a 350mb Xvid video file and when converted on LOW quality came to about 100mb (normal = 120mb HQ = 160mb) and the video quality was very good.
I also made this at about 5am, so i do sound tired and the commentary waffles a bit, i might redo it if i feel motivated.
Enjoy!