UPDATE 1: Updated to support the original QU-BD Anubis hotend.
I have been using ddegonge888's extruder design (http://www.thingiverse.com/thing:296670) on my OneUp for a while, and I can't say enough good things about it. I've been considering making the switch to the MK8 drive gear, and so I modified his design to work with the MK8. The MK8 itself has a much smaller drive diameter, and so I had to make quite a few changes to the extruder design itself.
It also works with the original lever arms, so if you've already printed his original extruder design, the only thing you need to do to be MK8 compatible is print the main body!
I've also modified the tensioner screw to sit slightly angled, as it will provide better tensioning capability when higher tension is needed. As of right now, I only built it with the E3D in mind but I've modified it to include Anubis support. Just download the body files for your specific hotend.
As per the usual, both SolidWorks and STL files are included. Enjoy!
Print 1 of each part (Body, Lever Arm) and its mirrored counterpart. If you've already been using ddegonge888's extruder, all you need are the body and body_mirrored prints, and you can reuse the rest of the parts from the original design. Assemble and enjoy!