FreeBSD Java is based on Intel, so it might be possible to apply it to port Mustang for Darwin, the underlying OS layer of Mac OS X on Intel Macs. One more feasible idea about the porting is making a headless version of Mustang for Intel Macs, i.e. core Java without graphic facilities such as AWT, Swing, and Java 2D.

Or, we can just wait for Leopard (Mac OS X 10.5) to come up with Mustang :-)