If you want to find another site like this, it depends on your location. For example in my country, there is a site here named tees.co.id and I think they ship all around this country. So if you want to ask this question you better tell us first where you are so we can find the proper sites for you.
Anyway, I think that site looks promising.
Anyway, I think that site looks promising.
I think that site is available to sell some clothes in some countries. it just depends on the seller on tees.co.id. and I've ever seen a thread on local marketplace section offering bitcoin t-shirts on tees.co.id.
and if I'm not mistaken, I've also ever seen someone offered bitcoin t-shirts on goods section.
Tees.co.id is a company that will produce and sell products to anyone in this country, and we as the seller just need to make the design and give the price for the product. So it doesn't actually depend on the seller, because they will ship the product to anywhere in this country.
,but bitcoin market has greatly progressed in few years but it will take some time by major company to accept it as directly or indirectly as mean of voucher.amazon voucher exhange is already there so it is a good way to start. 
