I’ve been a few times to Vegas… A few years ago there was an artist just off the strip called Creeper (Stratosphere end). I only saw two pieces of his work, one being John Lennon and it was seriously good. I haven’t seen his work recently and don’t know if he is still around.

I would take the advice though from what others have said on this post and stay out the touristy shops and take a good look at the artists folios.