Just like to weigh in with my experience. I've taught left-handed people to play fiddle right-handed, and it does work. The only reason I do this is that it is nigh-on impossible to get a left-handed fiddle. It seems that because you are working with both hands anyway it isn't as bad as, say, learning to write right-handed.

I've been asked to convert violins to left-handed on several occasions - each time the potential customer has gone away when I've told them how much it will cost!

Efiddler