I found a litle l4d mod community with a nive litle map pack to make death toll and dead air vs maps. i set up a litle dedicated server on my main rigg to test. THEY WORK! COuple litle issues. one you need to lower shaders to medium and the only way i can get into them is to start on stock vs map and change it. Here is the link sincwe you need to install them to play on a server. http://www.l4dmods.com/forums/viewtopic.php?f=28&t=618