This is a elevator that is made from Slime Blocks in the 14w18a Snapshot. The world download has two elevators. The one made out of sandstone is slower while the one made out of obsidian is the faster one. The obsidian elevator takes about 13 seconds to go from bedrock to the sky limit.

The obsidian one, if you were to build it in survival, takes less redstone torches but requires more sticky pistons and slime blocks making it more expensive than the sandstone one. The sandstone one uses less slime blocks and pistons, but uses more redstone torches.

In the world it shows what one level of the elevator looks like. You can copy the elevator from that or use the MCEdit schematic and stack them on top of each other. In the world there is also a timer that shows how long it takes for you to travel from bedrock to sky limit. The timer measures in game ticks.