Parallax has a new mid-sized (13″ x 10″ x 5.5″) robot platform, called the Stingray, that looks pretty interesting, built around a Propeller multi-core:

The Stingray robot from Parallax Inc. provides a mid-size platform for a wide range of robotics projects and experiments. The Propeller Robot Control Board is the brains of the system providing a multiprocessor control system capable of performing multiple tasks at the same time. The Propeller chip provides eight 32- bit processors each with two counters, its own 2 KB local memory and 32 KB shared memory. This makes the Propeller a perfect choice for advanced robotics and the Stingray robot.

The Stingray retails for $300.