I don't want the 2.2.3 release to be held up too much, but there are some things being worked on in the proxy balancer code that would be useful to be available in 2.2.3. Mladen and JFC are working on the AJP stuff and as soon as they commit their changes, I'll be adding in my balancer set patches (to trunk).
But if 2.2.3 is expected to be sooner than that, maybe the hot-standby is enough for now...