Bukkit

If you're feeling adventurous: Add in a Lumberjack villager that can be positioned in a treefarm region (or a given cuboid area), when given an axe and a chest, he will chop trees down, gather logs, leaves, and saplings, place them all in a chest until it is full or his axe is broken, and replant saplings. I would love to see this happen!

This would be a huge adventure to code, but I can see about doing it. Actually sounds really freaking cool :P