Walking around Home Depot, in the Electrical aisle, I spotted a LB connector for conduit. They had aluminum for ~$7, and a plastic for ~$2.50. I bought the plastic as I thought it would be easier to cut/grind and modify. Plus I wouldn't have to worry about the chassis shorting anything out, like my aluminum flashlight has done. A 9V battery fits snugly inside. I have begun modifying mine. So far just ground down the "L" part of it to mount my switch, and removed the cover and ground it down to make the whole thing thinner. I'll post pics of my progress, but the following link is the basic item that I purchased.
http://electrical.hardwarestore.com/14-47-plastic-conduit-entrance/access-fitting-225441.aspx
http://electrical.hardwarestore.com/14-47-plastic-conduit-entrance/access-fitting-225441.aspx