As a side-product of the robot ball that I am building now, I developed a quick-release box for the Mindstorms NXT 2.0. It has a nice trigger mechanism that you might be able to use in your own Mindstorms MOC. Check out this page for the design, more pictures and a demo movie.
Earlier, I made a truncated icosahedron (a football if you will) out of Technic Lego. A downside of the design was that the ball was not very strong. It would loose a bit of shape under it’s own weight, and a lot more if you pressed it. I developed three stronger designs for the hexagons (see below), but got distracted by other projects. Today, back on this track, I finished a new version based on the design at the far right. And indeed, it is a whole lot stronger. It can roll easily and even stand some pressure. Since the pentagons are not reinforced and there is a tiny bit of slack in the hinges, it still looses a bit of shape, but I think it’s within limits for my purpose. So, I will now continue with the interior, to make it a mindstorms-driven self-rolling robot ball, or ball bot, or whatever.