[curiousphil]

Check out RiQ from PCS Edventures. http://riq.edventureslab.com/

Their brain box is designed to integrate (snap) with most of the major construction toys: Lego, Fischertechnik, K'NeX, Erector, Minds-i... This opens up the possibilities quite a bit. They also offer a bunch of great robotics curriculum that integrates with their product.

Disclaimer: I work for the company that developed the visual programming app that allows kids to program their robots via tablet or computer. We partnered with PCS on this product. I'm proud to say it's a pretty slick system.