Hi Coder,
I bought into the Amiga Club and this Party Pack deal that they had. I doubt it's hard for them to create a logo and place it on a t-shirt. I am much more interested in AmigaOS 4, MorphOS, AROS and coming versions of Tao-Group's Intent (tm) which AmigaDE is based.
If you want to make a cool Amiga t-shirt, mug, mousepad, etc then check out
http://www.cafepress.com . Just supply them with the proper image and you can make all the t-shirts you want, even just one!

I wonder why Amiga doesn't just use Cafe Press? It only takes minutes to do! ..well okay, minus making the logos/artwork.