I see another one has been built and its a nice one more retro vintage.Wonder how easy it would be to find the motor trans set up to build something like it,See ian has already spotted it... http://www.jockeyjournal.com/forum/showthread.php?t=76560
The 8 cyl looks like 2 CB Honda 4 cyl motors coupled together.
A guy in England does a bunch of stuff like that, building Frankenbikes.
The case halves might be welded together, not sure.
The thing on the end of the rocker cover is a oil pump.