I have developed a library for operating High Torque Rhino Servo DC Motors (available at robokits.co.in). Links:
The motor is rugged, provides high torque, has zero backlash, and is impressively precise for its price range. It consists of a base motor, a gear train, and a microcontroller unit (with closed-loop PID control), all built-in, which makes it a highly functional motor for varied applications, especially robotics.
Do check out the library and provide your feedback