I could push through even extremely tall meshes.. but ya, in some instances it was crashes into thin ones so hard it went over, but without rigidbody freezing those axis's, even setting a translate in the update doesnt help because its already went over by the time you can set it back.
I did do the prefab thing and that worked pretty well, just created a billion boxes though. ;p
Have you thought about putting in an option for collider thickness? When I set it via the inspector, doing and edit/commit always chnages it back.