It's been a long time since your original post and I'm sure you've already arrived at a solution. My solution was to use high-power R/C sail servos.
http://www.servocity.com/html/hs-815bb_ ... l_arm.html
The 4-channel Phidgets Servo card can't sink enough current to drive these big guys effectively, so I added an external power supply and just use the PWM signal from the card with a common ground throughout the entire circuit.
The card is interfaced to an applet I wrote as a proof-of-concept to control the servos when FS(X) is running and the sim is under Autothrottle control. To ensure that the throttles really disconnect when not under A/T control I added a power relay which is driven by the A/T FSUIPC offset.
My source code (and an executable in the BIN dir) can be downloaded for free here:
It's released "As-Is"... meaning that you might want to know a little about C# if you want to take it further.
If you have any questions, drop me a line..