Found the link! It's hard to find the merchandise for sale, but here's how:
Pick the image you like.
Click on "Buy Photo."
Click on "Merchandise."
Scroll the list of stuff.
Why do they bury this on the page? Weird.
But cute as can be. I have my mug in my office. I decided not to use it to drink out of, so that I wouldn't wear the image off by washing it.