Well, is there? Not one of those silly ones where weapons are impossible to come by, and/or everyone gets pushed around by a military/police faction. Specifically, something that is as cool as this video: http://www.youtube.com/watch?v=rkKl6eeYi_k (The looting for supplies, not the music)
DarkRP has a zombie mode I’ve seen used for this kind of RP. If people actually RP instead of playing it like Zombie Survival, it can be pretty fun.
http://www.facepunch.com/showthread.php?t=339999 makes it look like that was what they did in the video.