The art on this tshirt was created by Jimiyo (aka Jimi Benedict), an extremely talented artist who was born in Japan, but currently lives in the US.
Jimiyo used a combination of pencil-drawn sketches and Photoshop to create his masterpiece.
The tshirt is available for $24 (plus shipping) at this site.
I highly recommend checking out Jimiyo’s insanely good portfolio here.