Is there a good way to cap the linear velocity on a collidable object.
I described how to cap the speed of an object in that doc.
Also, does anyone have any suggestions on ways to keep the sphere inside the model at high speeds (the model is an enclosed mesh)?
I did describe one way to do that in my doc, too, although it can get a little compute-intensive at very high speeds [basically, decrease the fixedTimeStep parameter to stepSimulation and increase maxSubSteps to compensate].
Alternatively, use continuous collision detection. There's a CCD example, and several threads on these forums talking about it.