New Project Help?

OK, so I'm new here but still a huge fan of Arduino. I was looking to create an integrated Arduino with motor controllers and servo controllers. Like, an Arduino with more robotic specialization. Is it feasible? Would the voltage draw make it far too complex? I was going to have a range of 6~48 volts for motor controls alone and servos would have to be powered separately, (with the Arduino perhaps?), and I'm not sure if the number of batteries (AA, Li-Poly) would make the project useless in its tracks.

Also, I'm looking for a way to wirelessly control this "super-board", but many of the methods are really expensive (100+ dollars for xBee?) does anyone know of a cheaper way to control this board remotely? I don't mind creating a protocol (such as for infrared) but I need to understand the methods with which the arduino and it's controller (another arduino most likely) would connect. Help?

http://arduino.cc/forum/index.php/topic,148850.0.html http://arduino.cc/en/Main/Robot http://arduino.cc/en/Main/Products http://arduino.cc/en/Tutorial/HomePage