I don't know if Stasis Field Generator might be the right term though it has some revelents I mean you want to keep the content sort static and not unload hehe.
I made a video of talking about it:
http://www.youtube.com/watch?v=Myy4-Oq0hRA
Pretty much a generator that uses a lot of power that keeps a certain amount of chunks open for a cost of energy. I think their should be some trigger events like after 48 hours it auto shutsdown things like this. Even though on a SMP Server if you reboot it unloads I'm talking about people who abandon land months later when someone walks by no point of loading chunks up again. Maybe this can be part of the component maybe requires a special fuel to run it or maybe better yet you need some kind nuclear component as long as you can run it for at least 24 hours.
For SMP Servers if possible offer limits maybe the max size etc etc.
EDIT: Updated the URL.