I don't believe there was ever an actual group display. I think I had 8 built at one time, but that was before I was going to any Cons. Quite a few people built them, but the City standard took hold so quickly and incorporated all the important aspects of MM, I think everyone used that instead. Which wasn't a bad thing. We really came up with MM as a way to get people building small MOCs that could theoretically be attached. But the point was something small that most people could build. At the time, things were slow in the realm of Castle and we wanted a smallish fad MOC that would grab people's attention. I think it did that. It got some activity going and it helped get the City standard moving, I believe. I could be wrong about that though. I wasn't involved in developing the City standard.
I will try and find my printout of the MM standard tomorrow. 'Try' being the operative word there. Unfortunately, I don't think it has the list of the people involved. There were about 10, but I can only remember Alan (footsteps) and myself.