I'd like to burn Storyr's excellent Weatherpanel theme, PhatPhingerII and associated icons, into a ROM but I'm not sure how Weatherpanel would handle this. WeatherPanel is very old and has been patched together to work over the years. Typically it stores themes in the Program Files/Marsware/Themes folder but it can also access it via a storage card location of Storage Card/WeatherPanel/Themes.
The theme files and icons can be found here
http://forum.ppcgeeks.com/showthread.php?t=9606
I don't want to waste your time for a "one off" but at first glance does this look like something you could achieve? I haven't tried creating my own OEM's yet but probably could fumble my way through it.