If you want to make your own T-shirt and only you (like not selling them to anyone else), I would suggest the DiatrictLines website. There, you can use your own images and make your own shirt/jacket. I'm not really sure how you make your own design (if you're a really good artist, you could try Paint for Windows and maybe convert it into an image) (I'm not very clear how), but you can use any image you have saved onto your computer and add a subtitle or a caption. Then DistrictLines takes the design and prints it onto a shirt! I believe that's how they do it anyway... xD. I really hope this answer helped and if it didn't, well, there's always YouTube! Hope I helped and I bet once you do get your shirt, it'll look totally legit. Happy shirt-making!! (>^-^<) <(^-^)>
Many art supply stores will carry screen printing supplies, including rolls of screen printing mesh. This mesh has not used silk for many years. Now days it is made from some kind of artificial fabric like nylon.
When you find the store that carries the material, you can purchase it by the yard, or linear foot. Depending on the individual designs, you may need at least four different screens made, perhaps even more.
Canvas stretcher bars may not be sturdy enough for your purpose. I used to use one by two, or one by three inch frames, mitered and reinforced at the corners.