I dont have any profound ideas of developing another agile capability maturity model, becuase I personally believe in the need for 'capability immaturity', which gives freedom to innovate and experiment, yet we need a repeatable system in place for organizations to exploit the power of agile in it's entirity. From my consulting assignments, this is the pattern I am seeing with most of the organizations, when they go for agile.
At level-0 , everything is adhoc
At level-1 , some agile practices are implemented (most popular is the stand up meetings)
At level-2, all the agile management practices are implemented (product backlog, sprint planning, daily stand ups, demo meetings, velocity calculations, lessons learned, user stories, story points)
At level-3, the focus is on adopting the engineering practices (build automation, test automation, coding standards, refactoring, code reviews, pair programming)
At level-4, the emphasis is on aligning the H.R practices with the agile values and principles