Looking for certain clothing brands in Thailand?

My bf and I are after clothing labels such as Elwood, Travisty, Juicy Couture. We just visited MBK shopping centre in Bangkok and only found cheap ripoffs, the same in every store, we found the same in Koh Samui. We are heading to Phuket & back to Bangkok soon and are wondering if anyone knows of any places that sell these brands or even ripoff brands but something nicer. Are there any shopping centres we are missing in Bangkok? Thanks.