- Build a website to manage a monthly T-shirt design contest.
- Pay the designers who win fairly well ($500 a design).
- Encourage people to rate the designs, post comments, and more importantly, indicate if they would purchase this shirt if the shirt ever existed.
- Print shirts in small batches, selling them until they are all gone.
- Reprint shirts in small batches after enough people have indicate they would buy the reprint.
So basically, you let the public tell you exactly what they want to buy, then you make it for them. Don't carry much inventory. These people deserve to make a lot of money.