You bring up an important point, I think, unintentionally. Kids may be able to 'screw up and fix' the software components, but it would be very cool to also allow the same interaction with the hardware.

I feel like maybe a version of the RaspberryPi that ships assembled on a breadboard with replacement parts - more expensive, of course, to cover the increased manufacturing costs and extra parts - would be extremely useful to anyone interested in hardware design. (Of course there are other kits that do this, but I think that there would be some benefit to RaspberryPi offering it as well.)