You could just set up a reverse proxy on a third-party host (the 'trunk') which just calls the same path on your local server and returns the results. See:
http://httpd.apache.org/docs/2.2/mod/mod_proxy.html The original requestor, then, shouldn't be able to see which server the reply is actually coming from unless something is misconfigured or they compromise the remote third-party host and get access to the configuration... it will look to them as if the third-party host is the actual web server.
However, this will only work for people viewing your webserver and not outbound requests if you are thinking about doing anything else from it.
From the website:
"A reverse proxy (or gateway), by contrast, appears to the client just like an ordinary web server. No special configuration on the client is necessary. The client makes ordinary requests for content in the name-space of the reverse proxy. The reverse proxy then decides where to send those requests, and returns the content as if it was itself the origin."
You can even chain these together, though I don't see much value in that off-hand.