I stopped using a case for my x100; i either have it in my coat pocket or loose in my daypack.
With a domed hood (even narrower / smaller and closer to the lens than Bill's, from the looks of it), the chances of anything hitting the lens are minimal. And the rest of the camera is pretty rugged, it can handle some bumps.
I've handled my camera like that for almost 4 years now, and it's still running like clockwork.
The filters i only bring with me on holidays, and they go in the daypack.
Very nice use of the ND filter, by the way!