The Apache mailing lists have been mentioning mod_serf lately as an alternative to mod_proxy. It actually looks really interesting, and its even more interesting that is has been added to the trunk. It provides asynchronous communications, which sounds great.

Here’s the mod_serf homepage at Google code, but I recall someone saying that since its now in the httpd trunk, its new how will be the apache repository.

http://code.google.com/p/serf/