merge video-dummy driver to xserver?

[Jamey Sharp]

There's been discussion of merging video drivers back into the xserver
tree. How crazy would it be to merge just video-dummy for 1.9?

My motivation: I want to replace Xvfb, Xnest, and Xdmx with a stock
X.org server (and shell script wrappers for compatibility), which I
think means enhancing video-dummy with a couple of trivial features
from Xvfb, and extracting the guts of Xnest and Xdmx into a new
video-nest driver. I'd rather do that in a way that preserves the
history of where the code came from, which means having it all in one
repo.

Thoughts?
Jamey