I hereby claim the wonderfully oxy*****ic term, "deep skinning"

Deep skinning, as bizarre as it sounds, captures what I want from a theme engine. I don't just want the shape or colour of widgets to change, I want the ability to move widgets around, or even hide them completely (with the ability to slave them to other controls, if possible). I want to be able to rearrange toolbars and menus, too. I want to be able to replace scrollbars with something else. I want to be able to take any user interface element and run it through my "deep skin" and have it behave in a way completely consistent with my interface.

<pieinsky>I want to be able to take a handful of standard GTK+ media apps, and just through skinning, make something like Canola.</pieinsky>

If this were only the case, maemo Abiword wouldn't need to be stuck in an eternal Beta mode with a broken on-screen keyboard, the Debian version would "just work" on the tablet, and it would look like a Hildon app.