Robot size

Many of us favor bench scale experiments. Large robots are more expensive and may damage themselves as well as their surroundings. There is no need for anything larger than the iRobot Create. On the other hand our robots must be large enough to transport sensors and such things as solar panels. Something the size of  a Pololu 3Pi could carry the various sensors from the Arduino sensor kits but are too small to transport larger sensors like a Geiger counter tube. A society of robots might be of a few different sizes but in this general range.