Kevin M. said
Let's not forget about the nu. it would also have to be changed and then there are the pegs, to make a proper left handed they would also have to be switched.

On one of my fiddles, the G-string peg has its end untrimmed, and it sticks out a half inch.  I noticed that my hand was bumping into it sometimes, so your point about the pegs is well taken.  Doesn't seem to bother the woman in the video that fiddlestix posted though.

There is also likely to be asymmetry in the fingerboard.  At the bridge end, I believe it is usually a little lower on the bow side.