I hate to double post, but here's an update:

Installed Nvenabler.kext, which on normal boot would give me two blue screens... and that's it. No cursors, etc. The last lines that came up in verbose mode were along the lines of apci_smc_platformplugin (then some other stuff). Ran the login window fix from here:

http://www.osxjournal.com/fixing-iss...ation-started/

Just in case, but of course, no dice. I've installed a modified Nvdarwin.kext from near the bottom of this page for now:

http://www.insanelymac.com/forum/ind...c=139203&st=20

Which is generating the same dual screen riddled with artifacts as EFIstudio and nvinject. The only difference is now I'm listed as only 256mb VRAM in the system profiler.

My only guess is that there must be a conflicting file somewhere, but... I have absolutely no clue here. Does anyone have any ideas?