There is a bunch of X-UFO/X-3D/BL discussion over at [link]http://www.rcgroups.com/forums/showthread.php?t=664794[/link]
and over at the german forum [link]http://forum.xufo.net/bb/index.php[/link]
translated version [link]http://forum.xufo.net/bb/babelframe.php?trurl=http://forum.xufo.net%2Fbb%2Findex.php[/link]
The Multicopter section has many of the open source folks posting there.

I have a modded X-3D/X-UFO Alu-Tweety and an X-CSM frame on order and am waiting for the Brushless kit and 72MHz ACT reciever to become available.

Seems like the difference is that the UAVP is larger and a more stable Areal Video Platform ... and the X-3D BL is a smaller fun flyer with future addons like an ACC module for self-leveling, etc... both have uploadable firmware interfaces supporting full parameter tweek.

--Eric--