I recently ordered two custom iPhone cases from UNCOMMON a really cool case manufacturer I found poking around in some design blogs.  The uploading/order process was amazing and the site is extremely nice and intuitive.  There was an issue with the content of one of my designs due to the art being a naked woman.  I got a fast email telling me to call, and I did and it was approved for print and the representative was very helpful.  I am guessing that if your designs have more nudity or a more suggestive tone containing nudity or sexual situations, you may not be able to get your image printed onto a case through this company.  So that is the only blemish on what was otherwise an awesome experience doing business with Uncommon.  The cases are $40 + shipping and your art simply has to be at least 2000×2000 pixels.  The rest is up to you.