I'm hoping to use this with dammitcoetzee's pulley: http://www.thingiverse.com/thing:10174. I started to make this a derivative but his license doesn't allow derivatives. Honestly, it's not a derivative though because you can use it to mount a lot of things such as Stevewall's excellent block and tackle: http://www.thingiverse.com/thing:10549.

Print, bolt to something, put a long bolt through the center hole along with a pulley or block and tackle. Attach rope. Pull.