Bret,

Model gliders have tried most of these control ideas at least once in
the past 20 years. It's much easier with the servos and computer
controlled radios to get almost any mixing arrangements you can think
of.

In the case of the full-span flaperon: Once the flap function exceeds
about 25 degrees down, the additional downward deflection of the
aileron function does NOT create much lift to make a roll, in fact it
adds a lot more drag and really increases the adverse drag. The
upward moving aileron function reduces the drag a little, but doesn't
remove much lift, again resulting an adverse yaw but no real rolling
effect. In the models you can change the "rate" of the controls
(increase or decrease the deflection relative to the control stick
input) and overcome some of the rolling problems but not very much.
We don't have any mechanism in our "big" sailplanes (that I know
about) that can increase the deflection of a surface at different
airspeeds or by selecting a mechanical detent on a control.

Having tried full-span flaperons in the model form, several times, I
can say I'd rather not try them on a full size, where my life is on
the line.

Mike