WED Treadwell Motor System

[kresty]

Hmm, I didn't consider that since we use the 2nd stick for domes on astromechs, however you could do a dual-stick drive where each stick independently drives that related track.  (Doesn't really impact the wiring if you used the Pololu motor controllers, though you'd want to find an R/C controller that didn't return one stick to center).  The FrSky Q X7 has dual centering sticks (you can remove springs if you want airplane type sticks.)

One big difference between our builds and most R/C builds are that R/C kits are usually vacuformed or other lightweight parts.  We tend toward wood and heavier construction.  (In other words you might need bigger motors).  That said, we drive our mouse droid from a 12V R/C motor, and more normal R/C motors might be able to be used if the build is light enough.  (Our mouse droid is 20lbs and seems to do OK with that motor.  A lighter mouse droid is OK with the 9.6V motors.  Our Lego R2 is 60lbs+ and I wouldn't want to try him with anything less powerful than the 100W Scooter motors).

Also check out the robotics sites for tracked robots, which are reasonably popular.  Purpose built robotic stuff might be pricier than DIY mounts, and probably aren't the perfect size for a droid build - but they can probably give reasonable ideas about how other folks have done tracked vehicles.