ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.
One of a set of tools we're offering as a way to say thank you for being a part of the community.
http://httpd.apache.org/docs-2.0/mod/mod_proxy.html
Beware of open proxies, and remember you would be using it as a load balancer essentially, so don't set up any features you don't plan to use...proxies can be dangerous.
Otherwise, you might need to look at hardware solutions like Cisco's F5 (BigIP)