I followed all the steps which appeared to run successfully on Ubuntu 12.04 b2 on T420 and I was left with low res screen and a Ubuntu desktop that would no longer install nvidia driver packages via apt.

Did not make any real difference whether integrated, discrete or optimus was selected in bios.

U12.04 fresh install did offer 2D ‘unknown’ driver/display.

However was amazed that Skype wouldnt install (lib32) and stupid side layncher froze repeatedly.

Better than my experiences with 10.10, 11.10 but still crap and wasted so much time.
10.04 seems to be the last usable Ubuntu distro.