The Emu Mini 2 is a small (less than 30x30cm footprint) low cost (less than $500 USD), 4 wheeled robot that is intended as a basic platform for the RoboCupRescue Confined Space Challenge competition. It is a starting point for students from high school (Year 9) upwards to experiment with solving real challenges in this domain.
It was developed by the Intelligent Robots Group at the Department of Computing, Curtin University.
See it running around here!
Here are some notes from a build session recently held at Scotch College in Perth, Western Australia, where three of these robots were constructed with Design and Technology teachers from Christchurch Grammar School and Scotch College, and undergraduate students from Curtin University.
STL and Sketchup files uploaded! Please visit http://www.thingiverse.com/thing:813910 to download them. Note that this is still very much a work in progress!