iRecommend: is a great place for just about everything customizable on the planet. 
In addition to the usual items like custom photo mousepads, coffee mugs, T-shirts, and sneakers are more unique items such as customizable cases for mobile devices and tablets, postage stamps, even mini speakers!
Most noteworthy is their customer service.  If it’s not right, they will take it back, no questions asked.  They’ll work with you until your 100% happy.  They even send you a follow-up email to make sure you’ve received everything in good order.