Now this wouldn't be a very fancy gadget but it could prove to be of use to those of us that are not skinners or anyone.
How about a Banner Gadget, one that allows you to put a banner on your desktop without having to use a graphics program (Paint.net, GIMP etc) and modify someones wall. I'm doing Suites right now using Theme Manager and it would be nice to have a banner show in the desktop screenshot with the name of the Theme being used.
RomanDA has a very nice Holiday Countdown Gadget that could serve as the example, have some built in banners of different sizes and shapes and skins with control over font, font size and font color, maybe even background color. If possible use another gadget, Rainbow Clock 1.0 by Vad_M to use how he gets the WB Theme you are using. Maybe even be able to have multiple banners on the desktop and be able to move them independently of each other.
Like I said, nothing fancy but it could be usefull.
EDIT: Moving text from right to left would make this very interesting also.