Lauren Klein and John D. Smith recently ran a series of interviews with people who coach community of practice leaders, and with the coachees. They are publishing part of the results and the first conversations around them.
A lot of my work as community manager is coaching the leaders of each CoP, both directly and through different groups, about techniques, goals, and context; online, on the phone, offline, whatever. It was found interesting enough to participate in the research and (seeing some of the other coaches in the project) I can only take that as a compliment.
I have seen a draft presentation and listened to a conversation with most of the other participants (missed it, as usual). The aggregate materials look very interesting, it should give fodder for interesting results.