I have a phD in Zombietology and have played and produced zombie themed games. It is harder then you think to put together an event like you are talking about
It is hard to find a good venue for this in the states that are willing to deal with the paintball mess.
If you can find a field that is willing to shut it doors down and find enough volunteers willing to be stitched up good luck.
Plus you need to beta test the scenario to make sure it is balanced so that it isn't easy and still not impossible for survivors to win.
It takes a lot of planning and time to do it right.
There is already Undead state, resident Evil High Rolls, and Vipers Resident Evil zombie scenario games In the next couple of months what more did you want?
Come to San Diego for a game I am doing November 10th at Giant Barona. We are doing a Red Sno games based on the movie Ded Sno