I've made a simple usplash theme for mame cabinets. I used a guide from the net and recompiled the xubuntu theme with my own images. Luckily the xubuntu theme is blue so I didn't have to change too much.
It should have 640x400, 640x480, 800x600, 1024x768 resolutions in it. I have tested it my end on ubuntu 9.04 and everything seems to be working.
The easiest way to use it is to install and use start up manager:
sudo apt-get install startupmanager
then
sudo startupmanager
When it loads go to the Appearance tab, choose "manage usplash themes" then click "add" and choose the "usplash-theme-mame.so" file that I linked below
http://www.megaupload.com/?d=IA0382PYHere is what the theme looks like (the progress bar is missing in the pic but it does show during boot):
As I said, it all works at this end but I can't guarantee that your computer won't throw a fit. Try it at your own risk and all that.