While neat idea in itself, it's quite hard to e.g. script making of buttons. Also, the NuvoTheme took maybe a few hours total for me to do, so if you take the current theme as the starting point, it's not a whole lot of work to turn that into whatever you like.

Next version will have a file that contains the cropping information, so perhaps you could use that as the source for gimp scripting.

But I think that the next steps for me are to add the few missing things, like the most common icons and such and then to start making the package for 2006 edition.

After that, perhaps something along the lines you described, could be implemented.