I'm back to LightDM. LoL!
I've been chomping at the bit, trying to figure out of way to install Linux 3.10 on this legacy machine.
Finally came up with a winning combination, except GDM won't work, again...
LLVMpipe generation is slow, e.g. laggy, but GNOME3 Staging fired right up.
Current Date/Time: Sun May 26 10:45:04 MST 2013
Distro Release: Ubuntu Saucy Salamander (development branch)
Kernel Release: Linux 3.10.0-031000rc2-generic
Gnome Release: GNOME Shell 3.9.1
Unity Release: unity 7.0.0
OpenGL vendor string: VMware, Inc.
OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.2, 128 bits)
OpenGL version string: 2.1 Mesa 9.2.0
Desktop looked wretched on Linux 3.9.2, but Linux 3.10-rc2 worked a treat...
Anyway, this'll do, until I can come up with a patch for nVidia-304 (or official support is available).