Hey, I am not sure what the policy on shameless self promotion is here so apologies in advance if this violates some rule or is just in poor taste.
I currently run a LARP called Via Nox (with a lot of talented help), which uses the Vampire the Masquerade setting and the Requiem rules set. We currently have about 50 to 60 regular players and, after 4 months, have worked out most of the kinks as far as growing pains and rules.
Check us out at http://vianox.midnightespresso.org/ for rules and information. Feel free to ping me with questions, etc. We run every other Friday with our next session on the 24th.