Hmm, I'll definitely give it a shot. Gotta get the Megaman Theme I promised off of my church's Wii, because I apparently didn't keep the source files. Idiot, I know, but I was erring on the side of caution, limiting what was on the Youth group's SD card to only what was absolutely necessary.
EDIT: [Farnsworth voice] Good news everyone! Extracting the Homebrew Channel save file yields three files, one of which is the theme.zip of the current theme! All I need to do is make a new icon.png, a new meta.xml, and then repack it. Thanks a lot!