I've spent some time creating a world edit mod, and I wanted to share it with the community.
Link to my code:
Instructions are in the README.txt
Pos1, Pos2 (left and right arrow keys)
Cube (toggle between functions with right shift)
You can now type block names instead of IDS.
Void World, Short Superflat, Large Superflat (Toggle between world with up arrow) (LAG WARNING)
Savestates (Right control to save the current world, Right alt to load it)
Replace, Replacenear, and use block names.