Hi Beth, if you are concerned with cosmetics of the URL and you don't mind using an outside intermediary, there are a lot of URL shortening services out there: bit.ly, owl.ly, goo.gl, etc. These may also provide some enhanced tracking if you care about that.
I agree with Joe, though, it's a losing battle to attempt to hide your site structure, web server, or anything else. Assume that everything about your site is publicly visible and accessible, except (hopefully) pages and other content secured by roles, and files stored by the shared files feature.