Fender and Rickenbacker both toyed with fanned fretted guitars in the late 60's, neither of which went anywhere. I've only played a fanned fret bass, and I didn't get on with it, probably because I'm not very good in the first place!
They did the same with their bass too of course. I don't know the answer as to why, I'm guessing it looked more balanced with a more substantial headstock, and less of a 'straight stick' looking neck?