The drill motor seems like an interesting idea. If one is handy enough mechanically, something like this might work. Why not have the fabric roll up on a top rod like a roller shade and simply have the bottom weighted with perhaps a brass rod running through it? Perhaps you could direct couple the top roller to the drill motor somehow. That's how I coupled my masking system to DrapeBoss motors (discontinued).
http://www.kathiejohnson.com/HomeTheater.html
The only thing I might suggest on this type system is that flat fabric hanging down in front of the screen isn't going to be very exciting, but would certainly be better than nothing.
If you had access to someone who sews, you could consider an Austrian or Roman shade approach, only using your drill motor and a rod at the top to roll the strings up on. If you look at the BTX rod, that's all it is, but it has little drums to roll the cord up on so that it stays in alignment. All of this stuff is mounted on a 1x4 which then mounted to the ceiling.
Both of these shades use a series of cords running down from the top through small rings sewn on the back side. The cord is fastened at the bottom and the fabric folds on the Roman and bunches on the Austrian as it comes up. A brass rod is used at the bottom for the cord to fasten to and to provide weight. You would need to find a store of some sort with one of these made up to look at the construction technique.
Whatever approach you might consider, be sure you include limit switches so that your system doesn't overrun and rip itself apart.
Deane