I'm impatient, and lazy, so...
Video of prototype is here: https://www.youtube.com/watch?v=fk1CsNBUk3o&list=UUv_zm49u-RjnCJVwhUO-ecA.
Hand crank version is here: http://www.thingiverse.com/thing:426305.
The finger cams are interchangeable with those of Impatience, so if you like the Impatience action, use those cams.
Designed using Sketchup 8, and printed in PLA on a Makerbot Replicator 2 using Makerware 126.96.36.199.
I purchased the following parts:
1) Gear Motor - Pololu part number 2366 (http://www.pololu.com/product/2366).
2) Coaxial Power Jack - Radio Shack part number 274-1583.
3) 1.5 Vdc Power Supply - Radio Shack part number 273-315 with the "N" style plug (273-345, you get one free with the power supply).
Study "Assembly Motorized.skp".
Print 5 "Axle Appendage.stl", 4 "Arm Finger.stl", and one each of the remaining parts.
Assemble as per "Assembly.skp".