I managed to create a small(ish), 3-floor piston feed-tape elevator that works like a real elevator. If the elevator is not on your floor, you must call it, and the doors even close while it's in transit.
Here it is in action: http://i.imgur.com/UFgGNTa.mp4
The piston feed tape, oddly enough, took less room than all the logic circuitry.
I think it would also be possible to integrate into a build, since almost the entire elevator is flush with the wall (the floor buttons do go off at an angle, though)
"Just a redstone guy"