I found Sakel's code repository for his wonderful SurvivalX server that has since been taken down. His repository is a treasure trove of good survival server mods. I particularly like the obsidianmese and the mobs spawners mods. There are other good mods here that can't be found anywhere else. I am going try to rework the obsidianmese mod to fit well with sara's survival - I really hope you will add it Unreal.
here is the link to the repository, take a look at the codes when you have time: