Got this working on Jaunty on a Dell CPx. I mostly followed 216. Differences:

1) wget instead of git cloning latest (thanks ModelR for the info about later versions not working)

2) sudo cp *.ko /lib/modules/`uname -r`/kernel/drivers/gpu/drm/ (instead of char/drm/) - this overwrites the default drm.ko and prevents mach64 complaining about incompatibilities

3) xorg.conf didn't exist by default, so I made a new one and pasted's excerpt from 216 - worked fine with no additional changes.

Hope this helps.