There are a number of islands down there with almost 100% Muslim local population. Koh Sukorn, Koh Tarutao, and even Koh Lanta. All of these places have some tourist facilities, and the local Muslim population are more genuine and friendly than the other Thais who have relocated there to serve the tourists. I've had some good times there, and always found a cold beer. The south of Thailand (other than Phuket) is my favorite area, nice beaches, and you can get laid every day in Koh Lanta and other places with little difficulty. On Koh Lipe, I banged a different massage girl every day.
I was in Sungai Kolok for a night last year when the train was severely delayed, and I did not want to cross into Malaysia that late and try and find a taxi to Kota Bharu. It's your common border town, but the number of western tourists is very low. I found a 500 baht/night hotel that was clean, had my last pork meal for awhile :) and I hit a few beer bars. All the girls working there were from Isaan, but with mostly Malay Chinese as customers. Had a ST back at the hotel with a GG from Nong Kai - a long way from home!
I think this report is a bit sensationalist, but that's Patrick Winn's style.