Our demobot shown built with GM3 motors (since replaced with GM2) on an Sintra base (extra).
These aren't kits, as much as they are an inexpensive bag of components so you can build yourself a Symet.
For true DIY, hack the included cassette mechanism into a solar-powered device using the high performance Miller Solarengine which converts light into impressive bursts of energy! Rapid fire, SCC2433-MSE version.
Herbie the Mousebot is a very quick, easy-to-build, light-chasing robot kit with functional whisker and tail sensors!
This epoxy-encapsulated monocrystalline solar cell generates a nominal 4.5V / 18mA (sunlight) from a 24x33mm package. And has an integrated solarengine circuit board!
This big brother of the SCC3733 is also an epoxy-encapsulated monocrystalline solar cell, but this one offers 8 volts and 44mA in a 37 x 66mm package!