See https://www.virtualbox.org/ticket/10293#comment:16 . The guest additions
build for me (using VirtualBox 4.1.8) in F17 and Rawhide with X.Org 1.12 support
(and no need for setting $MAKE to avoid the OpenGL error), so by using hardware
passthrough Gnome Shell is much faster. The next release (probably 4.1.9) should
include X.Org 1.12 support.
VirtualBox 4.1.10 has just been released, and X.Org 1.12 is
supported.
I wish the Linux guest 3D driver was fixed. It still hangs due to some
threading issue. The Windows guest 3D driver seems to be much more
stable though.