I think you will find this thread very interesting http://www.dreamviews.com/community/...ad.php?t=64838

I think it makes more sense to just imagine practicing than 'waste' lucids on something like this though, when instead you could be doing things like summoning things you can't experience in RL. Like you said, famous violinists, composers, expensive violins, concert halls, historical concerts. Something like teleporting yourself onto the Titanic and playing with Wallace Hartley as it sinks, when you could spend 'mundane' time practicing.