I'm already doing all this with python scripts for Inkscape - draw the entire UI in Inkscape, name things in the DOM appropriately, run a few scripts -> MOAI code (Lua) or C Code (SDL_svg).

Haven't quite got it ready for launch yet, but rest assured the idea is not new. There have been Inkscape exporter tools for this sort of thing for years, you just have to know where to look (inkexport, &etc.)

PaintCode sure is pretty, though.