Hiding non-standard ports in the address bar?
Solution 1:
One may set up a sort of portal using Apache with mod_proxy on :80 and make it to proxy requests for anything:anywhere.
Solution 2:
Is there a way to disguise and/or hide the port number from showing up in the address bar so that visitors don't know they're not on the standard http port?
No, and there shouldn't be. Leaving a mechanism for sites to "hide" anything in the URL bar would be very bad on multiple fronts.