reduce minimum mob spawn range and disable mobs being automatically removed

http://minecraft.gamepedia.com/Spawn

in here it says mobs can only spawn 24 blocks away from a player, is it possible for a plugin to configure this?

also this:

is it possible to disable completely? i want mobs to always exist in world, and never deleted. so they exist until killed.

 

@disgruntledpig The first one is either in server.properties or bukkit.yml. The second one is a really really bad idea, because you will eventually have an obscene amount of mobs in your world and the server will lag like there's no tomorrow. If you insist upon it, put a redstone clock that won't freeze attached to a command block saying "entitydata @e[type=!Player] {PersistenceRequired:1}".

 

no there is no option for it, i want to reduce the minimum spawn range, not the maximum! yes i understand there can be lag eventually.