Look at this image. It's 40 x 120 inches, so it's nice and big (the link has the small version). It took 11 months and has over 15,000 layers. It's really nice, but it seems like a lot of work, too. I would be printing that thing out and selling it at local art galleries.
http://www.bertmonroy.com/fineart/te...eart_damen.htm