I used to think Thai language is not a type of language that can be adapted into rap/ hip-hop music. Still now, I still think Thai sounds a little awkward in hiphop rhythm.
The best one I can think of is Joey Boy--long time rapping devotee. I've seen many groups (think MAF, Bazoo) that have come out with some hip hop senses, but don't go as far. Thai market always welcomes new waves and Thai consumers, especially teens, will usually support anything new, hip and MTV-ish sounds. But this kind of short-term support usually doesn't last long. Soon, these rappers wannabe start to fade away. Out of all, Joey Boy still stands.
Recently I saw his MV in Youtube "Rai-Gor-Ruk"--a more slow, less hip hop version of his music (see previous post.) Love every bit of it--lyrics, rhythm and Joey. Good point he's made there.
Wish temperature in Thailand ain't that hot. If that would ever happen, it'd have done some of these guys a favors as far as clothing.