Today I've managed to work on bits and pieces on the minimal support for VX855 graphics such as ensuring the viafb driver works on x86_64 builds as well as a preliminary patch to get VX855 supported by viafb.
I've also played a bit with openchrome and got it to the point where it can display X11 at various resolutions on a CRT (analog VGA out) including hardware accelerated cursor support. The patch is not yet posted, but I hope I'll soon find time to complete this.