URL Redirect iRule Question

What you're asking for could be really easy, or really hard, and it depends entirely on the application you're sitting in front of. For example, just to go to Google Docs, the browser touches no less than 35 separate servers. This would be a nightmare to proxy even for ProxyPass. If the application is not that complicated, then I'd say ProxyPass would be a good fit. The idea is that the remote application would IP space would be assigned to a pool, and ProxyPass would rewrite incoming and outgoing URL references.