I'm still in the phase of documenting how I want it to work, trying to include things like failover servers for the primary broker and a protocol for applications to communicate with so it can tell backends to move to other servers and such. I'm going for a fully service agnostic approach, which from what I gather from your docs yours is too.
I'm also plugging in a LRU queue and a queue for waiting replies to route a little more securely (response not in a wait queue, discard it).
I was just getting to the point of trying out some code to wrap my head around everything when my schedule changed and I ran out of time to work on it. Going on a vacation sometime soon and planning on spending some quality time on the project then. Vacation will include no internet access so I got to do something to keep my brain busy :)
Being able to add/remove workers without having to change a config is also one of the pain points I'm trying to solve and was one of my first motivating factors, glad to know I'm not the only one who wants to fix that.