Minecraft Mod - Floodgate Beta 1.7_01
Floodgate block can be used as either a floodgate, allowing toggleable water and lava falls, or as a trap door. When you place the floodgate control block, it will place a gate in front of the control block in the direction you are facing.
Applying redstone power to this will remove the gate. Use the control block to open the GUI where you can place supporting blocks that will replace how the gate looks. Requires ModLoader.