Hey guys, glad you're digging into the technical stuff of the dash.
Few tips / tricks:
1) You dont have to be in XZP format to use the skin, you can use Xuipkg /U default.xzp and extract the files as a folder- just rename the skin folder and the name tag in skin.xml for it to show up in the skin list... with it set up this way, you can make changes without having to modify or rebuild an xzp (and you can keep the default skin in tact)
2) You can add as many backgrounds as you want- you don't have to rename existing backgorunds, you can just add more to inside the taglist (same thing with stages)
3) Same stuff applies to tab colors, icons, etc, you can add as many as you want, whole different themes- when we wrote this customizing stuff, we were anxious to see what everyone comes up with. Heck, if it's badass enough, I can add it to the release, who knows...
Hope this helps you guys with your customizations....