community backed legal entity to defend bitcoin related projects is a must
I haven't read this thread yet and I don't think I need to, but this is a direct response to the title only:
You don't want an organization to "defend" a utility, you want a standards committee to maintain it unofficially. The more legal issues there are, the bigger a target any 'official' organization would be. What you want is something like the FED, not the Treasury.