I built a slot car layout for a customer once that motored down suspended from a ceiling in the basement. Got a lot of stuff from Grainger as far as motors, limit switches, pulleys, ect. Unless you have some kind of clutch (like modern day overhead doors do) I certainly wouldn't want to rely on X10 for motor stop. The limit switches I used were actually full motor current rated so you could use them as back up fail safes. X-10 is still a little flakey, I use it exclusively everywhere (all my switch locations are 6400/16400 transmitters) and sometimes there is other bus traffic either from my HA controller or another person pressing a transmitter somewhere. Most of the time they'll re-transmit but you can't count on it. Idec has their mini PLC's now that are easily programmed for local appliance type control, might be just the thing for your app. Check out thier smart relay [Link: idec.com]