I bought a Scary Trousers tee at the SD ComicCon. Large was the largest size available at the time, but I was assured by the helpful booth-elf that the shirt was a polyester blend and wouldn't shrink, so a large would be plenty large (pre-washed, it was).

Let's just say that rumors of non-shrinkingness are overstated.

But I love the shirt - shrunken or not.