How about a 5V Arduino Fio?
I really like my Fio with it’s integral Xbee socket, and to plan to use it as a wireless robot controller. But I am beginning to realize that I’m going to add a fair amount of level shifting circuitry to interface with the 5V sensors and motor controllers I already have. Part of the attraction of the Fio is the small package it provides.
I’d be certainly be willing to pay a few more dollars for a 5V Fio that had an additional voltage regulator and level shifters on board for the Xbee interface.
Thanks
Paul G.