We have a Wordpress site using latest code AFAIK: http://www.hellphonefilm.com/shop/
We just added Shoppe plugin but it's not picking up CSS properly from theme for all elements. We tried their documented process of customizing the shopp.css file, but it's not well documented and we are not CSS wizards, so our changes either had no effect or caused more problems.
All we really want to do is get the black text white on the "Bestsellers" shop view and then when you click on a product, get the descrip text white as well. We've posted in the Shopp support area with no love yet either.