Face it, putting a GUI on something like QEMU is going to require at
least a one per desktop/platform effort. And that can best be kept with
the GNOME/KDE/etc software repositories because they require constant
updating on the schedule of the rest of the desktop environment to stay
current.
In the development version of my Java frontend for QEMU (JQEMU) I've
already integrated the Java VNC client from TightVNC and it works like
a charm without any speed overhead! And it feels just like VMWare...
Since Java is already available for a large variety of platforms this
wouldn't require a big porting effort...
Christian