I dunno... why didn't we get a number of things? The Model X "needed" the doors if you go by what the Tesla folks are saying. I don't think the Model S needed them -- they got cool door handles anyway.
The OP was talking about suicide doors, not falcon doors. There are a lot of issues with suicide doors, including trying to get people into the front and back rows at the same time. They're great if you have a chauffeur.
Wasn't there a Honda Fit or something that had a suicide door? I like them and they are really easy to detail There was one thread on here where the doors when completely under the car or something- that was really cool- can't imagine it on the Model S though (it may be too low the ground)
"Under doors" http://www.youtube.com/watch?v=xGRzPFUlIeY "Weird doors" http://www.youtube.com/watch?v=pbqnLxrgui0&feature=endscreen
The MINI Clubman has one, and from the linked article it sounds like the future standard MINI hardtop might be getting them too.