I'm needing to build a standalone webservice for Mailman that our content manager can access. I'm most comfortable in PHP, so it's probably going to be PHP instead of Python.
But it will be needing to support authentication for usage. I'm planning on it just being a wrapper for the command line tools. If folks are interested, I could contribute our code as it goes. All our work here at the City of Bloomington is GPL. Either way, I'd be very interested in seeing a native RESTful interface come with Mailman