Hi, I've been toying with the idea of one of two programs:
a filter that will mulch the source code of X programs to use the GUI toolkit of your choice, or
a generic wrapper for GUI toolkits that can be easily switched to use any one you prefer, perhaps including a similar filter to assimilate unsupported programs.
I think utilities such as these would help to eliminate the cruft caused by having to load multiple large graphics libraries, open the way for fully thematic interfaces, and help users that are disadvantaged or just prefer a simpler X server. (In fact, limited ncurses support is a distinct possibility.)
Perhaps in the future we could extend the filter to other aspects of GNOME and KDE as well.
Redhat was thinking along those line when they came up with Bluecurve.
It ticked a lot of people off though - neither KDE nor Gnome folks were too happy... At least one core KDE developer employed with Redhat resigned over the affair, calling it crippleware...
I like the sound of your Idea, but I believe there is alot of work involved in doing this project, so I advise you to think it through very careully and follow all guideline involved in creating this project. I wish you luck.