The most recent research I've heard of is focused on the treatment that was applied to the wood:
http://www.sciencedaily.com/releases/2009/01/090122141228.ht...
Being able to hear sounds that can't be verified by instruments is not very scientific imo.
That said, there is a lot of stuff going on outside of the range of 'normal' recording and playback equipment, which is why a live performance of a church organ (for instance) is on a completely different level than the best recording of the same.
Violins however fall nicely in the range of modern recording equipment and if you can't record a sound from a violin it probably isn't there.