Fantastic list, Clint - and one that every artist should read when putting together a site. It's rare to see such a complete checklist published. Your suggestions clearly take into consideration the experience of the site visitor which is, of course, essential for ecommerce.

The only suggestions I'd add to your list is for artists to consider having an "FAQ" page which offers information like, "how long will it take to receive my package?" or "do you take returns?" or "Can I commission a special painting?" etc. and also to place more than one view on product level pages. I love to see detail shots, in situ photos, and even the back of a painting to show the hardware. Every detail helps move that shopper towards becoming a collector.