Actually, others have posted about this, and I used this feature just the other day:
If you go to your existing product, then click on the "Customize this" link, it'll take you back to the editor window where you can change out the graphic, then re-post it as a new product (be sure and remove the "Customized" stuff that gets added to the title of the product). "Most if not all"* of the original information will still be there, making it much easier to create a lot of similar items or change an existing product.
* When I say "most if not all", I've noticed that sometimes the categorization stuff gets lost, and your royalty will always have gone back to default too.
Nice feature, though!
