I've made something for my friends and me called Impossible Mode. I want to invite all of the Killing Floor players here to join us and have some fun. Currently it's under construction and we are testing it out and constantly improving it.
Join the Steam Community Group at: http://steamcommunity.com/groups/kfimpossiblemode
Join the Steam Community Group at: http://steamcommunity.com/groups/kfimpossiblemode