Dataflow computing in python
python.org has a Wiki page on "Flow Based Programming" -- http://wiki.python.org/moin/FlowBasedProgramming
The bottom line is that if you can reinvent the wheel in a small number of lines of code ( a few hundred) which you completely understand and can document, then do it.
This is an area where the abstractions used are not that hard to implement given some basic foundation tools. RabbitMQ is such a tool. Node.js is another. There are lots of libraries around that implement useful ways to manages dataflows, workflows, finite state machines, etc., but they have a lot of overlap and they tend to be incomplete. Probably the original developer just built enough to get over his initial problem, and since this type of programming was not that popular, there was not the critical mass to keep development going.
There is a lot to be said for ranking all the possible solutions by popularity, picking the most popular one, and putting your effort into making it work (while sharing your work, of course).