This design is currently in the running for WeLoveFine's My Favourite Pony (Rainbow Dash) contest! If you like this design and would like to see it on a t-shirt, click here to vote!
I thought the art would look better on a t-shirt rather than uploaded alone, so I decided to just use the contest submission itself.
Inspired by the numerous lightning bolt designs I've seen around Threadless. I thought it'd fit Dash perfectly with... y'know, her cutie mark being a lightning bolt and all. xD