Someone previously posted a link to a company that makes all different shapes of bumpers. I book marked it, why, I have no idea other than I am a Book Marking Fool.
You could most likely have customs made for yourself but the question is, do you need a thousand of them, or there about. Cause they probably have a minimum order.
Joss has their name on their bumpers, yet you can order plain ones from Joss. Which is to say, maybe they have a hot stamp or however it is done and do it themselves.
That would probably be the easiest for you.