There has been a 5 speed automatic for a while now, and according to the commercial jaguar has a 6 speed automatic.
The only 5 speed auto i've delt with was a ford explorer and in my opinion, they are a joke. Same exact tranny as the 4 speed one only the valve body is different to allow for an extra gear that basically does nothing except make you think your trannie is screwed up. If your going to build a 5 speed auto you really got to make the gear ratios work for the car not just to sell it.