be warned, tshirt design is a very very difficult thing to get right, mainly because of the post side of the process.
The idea of the design is only about a quater of the battle! There are sooooo many constraints on a tshirt design, believe me I know I've done my homework on this, you totally have to think from a different basis with tshirts.
What you have got is a peice of design that is on a tshirt, and printing that is all well and good with some transfer paper, a printer and an iron. The professional standard for tshirt printing is screening, and this is a process you have to understand a great deal about before you think about t-designs.
I'm not trying to be mean, but t design is a real war of idea, cost and printing.
fullbleed.org - series 8
Full bleed/Rob Dobi is probably one of the more famous graphic approach (rather than artist look up god machine or dan mumford for that), check out his work at the link, good example of relateable style.
this image came up in the process of my last job, the client said they would love to see it on a shirt, the logistics of getting that bear onto a tshirt are still keeping me awake at night! And I still havent figured it out!