Well, tonight I decided to be brave and installed Virtual Box 4.2 RC2. I thought I would re-try installing the new Guest Additions and see what happens this time around. Well, this is what happened after the reboot:
I had previously taken a snapshot of the VM before attempting the Guest Additions installation, though, so it was fairly painless to undo the installation.
I then jumped onto the VirtualBox Forums and quickly found this hint by Piercussion:
by Piercussion » 24. Aug 2012, 14:19Sure enough, I disabled 3D Accelleration like so:
I was able to get Guest Additions to work (partly) buy disabling 3D Acceleration and enabling 2D Acceleration. However, I'm still not able to use 16:9 resolutions and it crashes going in and out of full-screen mode.
And I was able to bump up the screen resolution to 1920x1080:
Hat tip to Percussion and cybervzhn for the tips!