I like POE a lot, and I had a quick go at the forking version, and tying it together with SOAP::Transport::HTTP. Unfortunately not knowing a lot about SOAP and the HTTP::* modules used, I'm not sure how to get them to cooperate. I don't really want to debug with tcpdump :-)
OK, scratch that, a bit more educated experimentation and I have it working!
Initial performance results seem promising. It's driving the load up on my dev box, I consider that more useful than them waiting in line to be processed. Production box is much (much!) more grunty and I expect it to scream along.