RE: aileron servo idea
I also use a plywood hatch cover, with wooded blocks to accept the servo mounting screws. I use 1/16 inch ply for the hatch. I maintain a 1/32" clearance between the servo and the hatch. I have purchased longer arms from Dubro but then you need a really tall horn also.
The 1/16th thick hatch is okay, but not quite as ridgid as I would prefer.
I suspect that the mechanics of such a servo would not present any problems for the manufacturer - we have retract servos with almost twice the standard throw. I would suppose it's a question of marketability.
Limiting the throw via a computer radio means you will need more powerful servos for the same force and throw of the aileron.