This post is timely for me. I just got a W500 w/ switchable graphics and Vista Business (32 bit) and am seeing similar symptoms.
Viewing Device Manager/Display Adapters I see only the "Standard VGA Adapter". BIOS set to "Switchable". Even with ThinkPad Power Manager and Power Manager Drivers re-installed w/ latest and latest ATI/Intel combo drivers installed, system did not recognize either the integrated Intel video adapter or the ATI discrete adapter.
Changing the BIOS selection to "Discrete" results in zero video display post-BIOS. Switching to "Integrated" has same issue as above - Intel adapter not recognized, still "Standard VGA Adapter".
I suspect problem with video adapter hardware as Vista won't recognize either. Called support, did the level 1 uninstall, reinstall, reboot, reinstall, rinse, repeat cycle and they determined hw problem as well.
Nuts b/c just got laptop 2 days ago...