Hehe...it is amazing to look back on this thread and see the progress that has been made on adding brushless to quad board's such as the X-UFO's chinaboard and X-base, and Draganflyer. They all mod very easily and fly great with the opti-isolator mod developed by Old Man Mike. Here: http://www.rcuniverse.com/forum/m_6316400/tm.htm. I've done this mod on all the above board's and they all fly beautifully with tons of power using the recommended motors and ESC's that OMM used.
Nick, you were certainly on to something with your idea of going brushless on the DF! I originally tried the powerzone BL adapters on the XUFO chinaboard and they did not perform very well. There seemed to be too much latency in the motor's response to the gyro's inputs. The OMM opti-isolator mod works very well. It looks like you were on to something when you found the PWM signals for the controlers. I would have liked to have seen your ideas there too.
And now there is the Spectrolutions experimental brushless DF board. Here: http://www.rcuniverse.com/forum/m_6531477/tm.htm and a very long extablished build thread stated by OMM here: http://www.rcgroups.com/forums/showthread.php?t=768115
Of course I know you are deep into Mikrokopter's now. I'm heading there too...slowly...)
Cheers,
Jim