There are none that I know of, because Thailand produces a blue mountain coffee up in the north by Chang Mai. Since Thailand produces coffee it charges a very high import tax. Something like three dollars per pound which makes it impractical to broker import coffee. I know some roasters that have it mailed to them in fifty pound boxes and manage to get around the import fees. I thing they have the boxes marked as something else like just beans. The blue mountain they grow is good coffee. I love they way they brew very strong coffee and add a little sweet milk.
You might want to talk with Mercanta Coffee (The Coffee Hunters) out of London. I know that they already supply one of the better roasters in Bangkok and likely have shipments regularly coming into the country. http://coffeehunter.com
Steve there are quite a number- most dealing with Thai greens. Thailand has a very strict quota systemn to protect the farmers in the North. You might want to talk to Chartree (Peaberry Coffee) or Sirada (PnF Coffee) both in Bangkok- both very nice and approachable people.