Penicillin and the Pull-out Method: A t-shirt of each please..

If you have ever been to backpacking in Thailand or aspire to one day go, you will more than likely end up in Kho San Road..the mecca for all foreigners to Bangkok. It is the place to meet tanned Australian backpackers in wife-beaters, braid your hair with synthetic florescent yarns, get a non-descript but cheap tattoo, eat greasy pad thai from a street cart and drink a sweet concoction of energy drink, soda and whiskey out of a bucket. Oh my twenties the stories you can tell. It is also the place where you buy the "Sure" brand of t-shirts -a momento most people return with as they are cool tees- well they were before everyone else got into it - and pretty trendy. But as far as black silhouetted faces of Bob Marley and Elvis on bright colours go, I get excited when cooler designs of OTHER, lesser known but still iconic figures come to my attention.
Which begs me to ask..why am I not seeing these designs by Kiersten Essenpreiss on T-shirts everywhere? Or on underwear? Or socks? Or tattoos?