MakerGear Simplified Extruder Block with Quick Release and Rear Motor Mount
This is the same quick release extruder block as the original except it is rotated 90 degrees so that the motor protrudes out of the back.
I built this as part of a bigger on-going project I'm working on to increase the Z axis limits, which can be found here http://www.thingiverse.com/thing:22887.
If you're going to use it, keep in mind that MakerGear's X axis belt will probably be in the way (I got around that problem by flipping my x carriage upside down, kind of a hack but it works).