Some time ago I headed in one of the most complete DIY photo/cinema solutions for low-budget productions, the OpenMoco. It seems they spent some time in prototyping a brand new shield:
The DollyShield is an adaptation of the Arduino Motor Shield v3 that provides directional PWM control of two DC motors, at up to 1A of current each. In addition to the motor drivers, it also provides a stereo plug with dual opto-coupled outputs for direct camera control, a 2×16 LCD, five user input buttons, and four auxilliary inputs or outputs through two stereo jacks. It is designed to provide an inexpensive and easy-to-use interface for two-axis motion control integrated with a camera.
more info after the break