Running InterWorx-CP through a reverse proxy

As we add new hardware and therefore more installations of InterWorx, we want to move “heavy” websites off to the faster servers. However, a common problem encountered is from people that have bookmarked the URL to “their” InterWorx, whom suddenly cannot login and think their site is broken, gone, hacked, etc. It doesn’t matter if we have a portal where the user enters their domain name and it forwards them to the correct InterWorx box, savvy users skip the extra step (as I would, too). (Side note: Clustering is not an option here. All OSes a

I am trying to create a reverse proxy that will serve as a consistent gateway to our InterWorx boxes. Similar to how InterWorx itself sets up a reverse proxy for the per-domain /webmail, /horde, /squirrelmail, and /roundcube links, I want to point to the correct InterWorx server.

I am having difficulty accomplishing this, as InterWorx appears to use absolute root-level URL’s (ones that start with a forward slash), and the HTML <base/> path is not defined. Because of this, I added mod_proxy_html to the arsenal (joining mod_proxy_http), which fixed everything but JavaScript redirects, such as the MySQL menu item in the control panel. I know it can do text-based URL replacements too, but that’s beginning to feel a bit too uncontrolled, not to mention the extra processing power required.

I’m asking for help and suggestions because I’m not sure if I’ve overlooked something obvious. Can InterWorx be configured so it plays nice with the reverse proxy by using relative URL’s? Any ideas?