While we are "doodling" for something to operate our doors. How about hydraulics. I had a new 48 Packard Convert (exactly like on BTTF) and it had a hydraulic pump in the engine compt on the firewall with tubes running everywhere.....first car I ever had with hydraulic windows, seat and top....tremendous power in a small cylinder. Same were used on Fords in those days. One time I sat on a window edge as I pushed the button and it raised me right up in the air! Much power!! Would require safety features of course. No opening of doors at 140MPH!! Also our daughter came back from Japan a few years ago and said the Mercedes car her host family owned had a gadget I would love....The grandpa pressed a button up front and CLOSED the rear doors......she said also they were on Taxi's they rode there....of course that would not need the pressure ours would take. Just thoughts FWIW. Murray Vin: 05962 Lic: DMC-XII