Holy crap, this is extremely cool!
It never occured to me that I could store info in the registry!

I have a ToolPak Add-In that I dsitribute internally, and currently I use cells on one of the hidden sheets to store user info and version info. Sometimes its tricky to juggle this stuff when updating an old version with a new version. Storing this info in place external to Excel and VBA would have some advantages.

I'll have to play around some more with this.
Someone should make a KB entry, if there isn't one already.