We have been discussing introducing a brand of kaka t-shirts for a while now here in Finland, and I believe it's now time to introduce the idea in further detail.
First things first: We would like to get you all committed to ordering a t-shirt for all the participants here (be it hanging at SD and/or #kaka, or just aware of the existence of either). As we're all more (or less) strapped for cash, we're naturally hoping to minimize the price of said shirt and thus looking around at different print shops and web services and asking around for deals before we decide upon which one to use. Hopefully price will not be what stops you from ordering one!
As far as the forthcoming shape and form of the shirt goes, we're hoping to be decidedly minimalist and thus gravitate towards a t-shirt emblazoned with the classic logo, in this vein (don't mind the picture :p):

A "HAIL KAKA!" logo,
white lettering on black fabric,
in medium small size,
on the front chest.
I've included a poll in this thread regarding the use of the exclamation mark in the logo - we should decide whether it should be there (as it has always been) or whether it should go (four letters in each word makes it look better).
Some further suggestions, such as the user's nickname embellished on a sleeve or something else written on the back were eventually ruled out because they a) felt too elaborate and b) things like nicknames might change as times go by. Less is more in this case, and I do believe simplicity will greatly enhance the general usability of the shirt.
As far as the colour choices go, black on white was also ruled out because it has less balls (though on a coffee mug it might work better).
There are two types of print we can try, normal and embroidered, though the material of most embroided products has to be rather thick so we'll probably get that ordinary print job done.
The size and shape of the shirt probably depends on the shop or service we use (as well as your general size), so more on that later. We might have to ask you all to submit a desired size, or we might just order a certain size for everyone.
Naturally there has to be a certain batch of shirts ordered, and as it does cost quite a bit of smackers to make say a 30-shirt order, we'll have to arrange payments, shipping and pickups beforehand. We might also pool a bit of money to get some extra shirts in case we get more members or someone ruins his or hers.
The Finnish deliveries will probably be easy enough, and there's a chance we can just send one batch over to Sweden too, but the rest might have to be individually mailed.
As far as having a look at print services goes, we did some preliminary googling and found out that Cafepress has to be ruled out because they have no dark shirts in their catalogue. While SpreadShirt do, they are unable to print digitally transferred pictures on them. Enok actually suggested asking them why, and they responded with the following today:
Digitaalisessa painatuksessa ei ole lainkaan valkoista väriä. Koska valkoista ei voida painaa, korvataan se kuvioissa valkoisella tai vaalealla taustavärillä. Tästä syystä voimme painaa digitaalisesti vain vaaleille kankaille. Olen pahoillani.
What this effectively means is that we'll have to get a non-digital print shop and work it from there.
http://www.kuvatikkaus.fi/ is a local print shop right next to my university. Quite expensive.
Basically, if everyone's on the lookout for services and shops, we'll get the shirts for a good price. Ganbatte! If all goes well, we can look at a coffee mug next! ^_^