minecraft.novylen.net

I can't tell you how many times it's disappointed me to go to my farm to find it not grown at all. Maybe allow donators to request one or two areas be loaded?

http://dev.bukkit.org/bukkit-plugins/chunkloader/

Not sure if it's too overpowered, or if it'd be just too laggy.

If anything it will lag the server, just afk at farms or work around them.