I don't know if there is a site just like gamiss but if you want to buy clothes with bitcoin you must exchange it first to $ and paypal as a payment method. Because most of the online shops do only accepts payment with paypal or any other authorized web site. If you are not unable to find some other site like this, well try my suggestion and use virwox for it.
There arecsome issue in some countries where they do not accepte Bitcoin on direct transaction on a specific business. But i do not see it as a bad thing because they also support Bitcoin but as an currency which need exchanges to deal with transaction. So it is also a big part for Bitcoin development in transaction so no doubt that it can be a more accepted currency in terms of business if all can see its full potential on the world of investments.