You may or may not be aware, but i’ve done custom t-shirts for myself in the past. On average one per year, usually saving them for the highlight conferences (one was WordCamp Phoenix back in the day).
For WordCamp San Fran, I am planning a shirt and wanted to get some initial feedback and some additional ideas for items to go on the shirt.
Let me know your feedback and suggestions. Even if i don’t use them directly, they help the decision and creative process.