Extreme Mob Farm
The Reaper
Version 1

Built using the same fall mechanics as my other mob farm, the Reaper is a forked tower design with the goal to pack as may functional piston traps as possible without sacrificing item transport and fall time. Two spawn towers share the same fall trap reducing wasted space if were to build separately.

Build Specs:
Requires Minecraft version 1.3 or higher
215 x 179 x 51
42,360 piston traps
Tall mobs only and the occasional slime.
Enderman and squid free

Features:
One Touch Piston Repair System: Press the button and in one minute it's ready
Force Shutdown: Flip the leaver on the Piston Repair System to shutdown the trap preventing any spawns.

Items/hr Yield:
These numbers are from my tests while building the trap.
134,580
135,600
138,540
139,920
141,000
143,640
146,340
147,240
152,040