[ubuntu] 12.04 - Stuck at blank purple screen after boot - Macbook Pro 4,1

I installed 12.04.1-desktop-amd64.iso last night via ReFit. The install went fine and the system rebooted. After I select "Ubuntu" from Grub now I am just stuck at a blank purple screen.

I tried the "nomodeswitch" kernel parameter but all that did was drop me into a text based login prompt.

I also tried the mac specific .iso but I couldn't even get the installer to run.

Any ideas?