It is larger than anything that I would want but the idea could be scaled down easily. It is certainly not the easiest design to make, but it is technically the best design that I have seen. I like easy as much as anyone but I generally put better above easy.
Many designs rely on putting an out of balance mass on the motor shaft which is easy but I often wonder how long the motor bearings or motor shaft will last under that king of loading. The Make it Extreme design uses an eccentric bowl actuator shaft mounted in substantial bearings and the motor is further protected by a belt drive. I think that with a scaled down version you could lose the belt and couple the motor to the working shaft through a misalignment coupling.