TL;DR: Vector graphics file for each design and permision to print it.
International shipping of this kind of t-shirts makes no sense. You are buying the image design (digital), not the fabric (physical). What I would want to buy from you is a personalized certificate that authorize me to print a limited number of Tees, posters, mugs or whatever, with the design I purchased. I would receive this certificate or permission along with a SVG file (or other formats) of the design by email.
Currently I could workaround this lack of offer by getting the best quality image out there of the design I want and then donating a few bucks true the "Friend Of Techdirt" option. This is not ideal, the quality of the image will probably not be good enough for most uses and well, I would like to have an official green light to do it.
I understand, that this thread was meant for "physical gear", and another one for "new blog features and subscription packages" is to follow. Well, that one does not cover this topic either. Right now, as Lisa Westveld wrote, non-US fans do not have a good option to get physical goods related to Techdirt, and this idea is meant to solve that. If I'm forced to stay withing the spirit of this thread, how about sending this certificate in a physical form by normal mail? That way this count as a bundle of physical goods with digital items.
Motivation, rationale and further thoughts:
Recently I ordered a bunch of products from the XKCD store. I live in Germany and the parcel was lost somewhere in the mail. They sent a second parcel, this time by a more expensive delivery system. When it arrived I had to pay a little more than 70 euros in import taxes for it. All I wanted was a witty t-shirt to show my appreciation of this awesome web comic and support Randall for his work. Instead they probably lost money on this order and I had to pay a considerable surcharge to German customs. Then I thought, why the hell I'm buying a physical good, shipped to me from the other side of the Atlantic, when what I really want is a digital design on my t-shirt that could be shipped to me at no cost? Well, XKCD had no donation option, so that was my only way to support them.
Also important is the fact that I don't particularly care about the t-shirt manufacturer, I wish to support you, and the less you expend making that possible the better. With this idea I spend less of my money and you receive more, win-win.
But, but, piracy... I understand that once the SVG is out there, "it's out there". But well, we aren't scared about that over here, do we? And certainly there's ways to monetize the exposure. I would be happy and proud to wear an added Techdirt logo to each of these designs.