Since I'm pretty new around here, I'm not too sure of this "community's" history. Has there been a solid (i.e. non-sock puppet) corps of members for a long time? Aside from the mods, how many members know at least one other member (in real life)? (I don't).
Anyway, I am down for physically participating in a city building activity. I might even be able to get some future UT charitable organization a small office in the club district in a building that houses other community minded organizations (among other things). But that would require an organizational infrastructure and a substantial voluntary commitment from at least a handful of its members. I would suggest the mods discuss that prospect and let the rest of us know whether it's something that can be discussed further. PM me if there's enough demand for a private meeting space to discuss this further in person.
Also, I don't think Spacing thinks it holds a monopoly on urban community organizations. The Toronto Public Space Committee has spawned all kinds of offshoot organizations and continues to do so. Spacing (the mag & websites) are but two wildly successful examples. Spacing has nothing but love for people who want to improve the city, and we would get lots of support from them.