I have managed to get a 64 bit image to the point where I can load VMMaker 3.8b6 from an MCZ file, and can generate a VM from recent Subversion sources (SVN 1546) directly from the 64 bit image. I generated internal plugins BallonEnginePlugin, BitBltSimulation, FilePlugin, and SocketPlugin along with external plugins AioPlugin, OSProcessPlugin, and XDisplayControlPlugin. After building the VM from these sources on an AMD 64 Linux system, I can run the 64 bit image on the new VM.
This is the first time that I have gotten a 64 bit image to be reasonably self-hosting with VMM and up-to-date SVN sources, so I thought it was worth a mention.
Dave