I was looking to upgrade the X-Carriage on my printer, and wanted a design that would serve several purposes.
1) It had to support LM8UU linear bearings.
2) It had to allow the extruder to be mounted tangentially to the x-axis, so that I could recover the print area that was currently being taken up by the extruder stepper.
3) It had to allow easy adjustment of the belt tension.
4) It had to have a place to mount an optical end-stop flag.
5) It had to provide good clearance for the hot-end.
6) It had to be as narrow as possible, so that it wouldn't reduce my print area.
After searching around for a bit, I found that none of the published designs met these goals, so I designed my own.
I found that meeting my goals would be impossible with the normal belt clamp design, so I designed a single-ended clamp which leaves room for the LM8UU bearings.
This thing is a bit tricky to print, particularly the belt clips, so you might want to try printing BeltClipTest.stl before committing to the entire object.
Thanks to Josef Prusa, and Greg Frost, who's designs inspired this.