Here's a neat SCARA-style RepRap. It was recently featured on ZDNet. I think I've seen some of this being mentioned on the Google Plus 3D Printing Community (update: yup, actually, it was first posted at Adafruit) -- glad to see it's coming along nicely.
One of the objections I had in my head about this design is that the printhead could sag as it reached further away from the mount. The solution? Move the Z axis to compensate. Clever!