In October 2005, I started organizing people into a discussion group about project management and maturity models. The scope of the group included many different models, including all project management maturity models and other types of maturity models.
The group had some great discussion, but we were not able to grow the group much beyond sixty members, and the on-line discussions were not as frequent as I had hoped. I am no longer actively recruiting people into the group.
If you are interested in project management and maturity models, I strongly suggest that you join the SdB+PM Forum. There are many people in that group discussing issues of process maturity, and you will find an interesting community there.
My hope was to create an on-going group that was vendor-neutral around the topic of maturity models. If anyone is interested in reviving that goal, please contact me.