I have not, good idea. 11.1V is within the tolerance of the board according to the datasheet, so I shouldn't need to regulate it down.
Most 'hobbyist' blogs suggest a 9V battery, but a typical 9V battery won't supply the current I think I will need.
I use ZIPPY Flightmax 2200mAh 3S1P 25C and IMAX B6 Charger/Discharger with my A-10 warthog (smallscale).
But that's not the point; I just wanted to warn you to be _very_ carefull with these batteries.
Or else...