I'm working on adding RFB support for QEMU. I've attached my
work-in-progress here. You'll need to compile and link against
libvncserver to make it work- I'm not an autoconf wizard, so I just
hacked my local version for now.
The whole thing works surprisingly well. I managed to talk to QEMU on
my Linux box from my LAN-connected Windows box with amazing performance.
It's a bit of a pain using the mouse over VNC since everything is done
using relative position packets. It might be possible to emulate a
Synaptics PS/2 touchpad (which supports absolute positioning and is
supported under Windows and X) to make this a bit easier, but I'm not
certain how difficult that would be. It might be easier to whip up a
special VNC client that supports mouse capturing. :)