Hey Malcom, I haven't beaten anybody up in at least a month! Seriously, I don't think it's a matter of fingering being more important than bowing - they're both important. Fingering just takes more small muscle control and bowing takes larger muscle control. Playing rightie works fine for me because my left is better at small stuff. (Although for some reason, I can tap my fingers, 1-2-3-4 on my rt hand and my left middle and ring finger come down at the same time. Go figger.)

A person who plays a right handed fiddle left handed would have to bo less upright, or less verticle and more horizontal. The bridge is higher on the right, toward the front of the fiddler, so he'd have to lift his arm up higher. The e-string tuning peg would be in the way. Not an insurmountable problem, but a major PITA.

I also believe if a person has already learned to fret a different instrument with a certain hand is going to have problems switching hands to finger a fiddle with the other hand. I tried guitar left-handed when I first got it and it felt very awkward. I think when I first started playing fiddle, I could have successfully gone either rightie or leftie.

And yes, there are degrees of left-handedness. I believe full on, right brain, do-everything-with-the-left-hand folks are pretty rare. I still say give the guy a fiddle and let him try different stuff.