A review for Die cut stickers by Doug Strock.
The process for requesting a graphic appeared straightforward and simple. I did encounter an issue attempting to upload the image, but I was able to send it via email attachment and was looking at a proof a few moments later. You will need to have the image in a final state because what you submit is what you get. I'm not sure if they offer a graphic artist to assist with creation of what you need, but they will definitely produce a sticker of what you send.
I would definitely order from them again and recommend them.