Hi Chris
I live in Australia (cairns) the Arbotix and the serializer MCU are a
good start the serializer (from robotics connection)
costs about $10 in postage, there is a good fourm at
i run this under ubuntu 10.4 and ROS
the arbotix with dynamixel servo sharp IR range finder for about $160
+ a drive base and encoders
will allow you to use the navigation stack (but not gmapping)
But on that site I found the roboard, basically a 1Ghz 486 based SoC with plenty of I/O. I can run ROS on this controller and wifi to my server if need be
Would the roboard make good starting point?
As for the rest of the hardware I should be able to source it all locally