Mmmm.. I don't think it would be terribly difficult to motorize a non-motorized screen roll-shade, especially if the unit already has a return spring of some kind.

The desire for I/R control warrants dedicating a $5 PIC to the task. The other parts would consist of a small, geared DC motor, LM293D H-Bridge, a couple of microswitches (for end stops), two pulleys, some string, and a long metal rod for the driveshaft. Plus a regulated AC/DC brick to power it all.

Cheers