OK, I'm just brainstorming here. What about a shirt that changes monthly and has an issue number like a comic book?
In this shirt you get the most important or relevant bitcoin news story turned into a beautiful piece of art (on the shirt) and it gets changed every 15th day of the month....
For example a recent shirt could have a German theme to it, and something close to: Germany recognizes Bitcoin.
The shirt could also have the price of bitcoin somewhere and other details that stay in the same place in its layout.
The shirt could also be the most inexpensive/standard shirt in the catalogue making people want to buy and keep buying it.
This may go a long way in building a customer base with people buying the monthly shirt in a row getting a small discount.
What is the thread in which you're selling Bitcoin Pride shirts in the forums? PM?
I may just buy my first bitcoin shirt in the next few days.
Off Topic:
There are many great products to be made in the BTC world such as a physical wallet (comes with most of the blockchain, enough memory and a way to sync from a wireless connection from a nearby cellphone or Wireless network (or connecting with its very own SIM card) Benefits of a physical wallet (extra security, maybe standardized offline backups through a usb port and automatic backup option)
An Electronic vehicle charging station that accepts bitcoin. (It probably already exists by the time you're reading this (or even before I typed it))
A file hosting service with quick download speeds that charges in Satoshis (0.0000001 BTC)
A jukebox in a cafe/ restaurant that takes Bitcoins.
A vending machine that vends money for bitcoins that vends bitcoins and money. People would be able to put in USD or BTC. (in a local business)
An electronic rechargeable coin that stores bitcoin safely offline (For storing large amounts of bitcoin offline safely).
(The first and last device in this list would work together really well, the last device would require far less memory and capability)
I can edit that last part out if this is too off-topic.