Rather than a window regulator motor I used the little gear head motor that Surplus Center sells, it's a rather beafy little guy, and we made a diamond plate house for it to keep the snow off.
The process was: 1) remove the crank and shorten the drive tube, 2) mount a flex coupling, 3) make the mounting house to fit, 4) wire it up to a fused circuit (this motor will stall out at about 13 Amps) and 5) switch with a DPDT momentary in a convenient location.
DrMac