If American, you will have to submit a w-9 to the bank and report the account to the IRS if the balance exceeds $10k usd at any time during the year. (Use online form FBAR)
Bangkok Bank has to give Americans an account if they have an Embassy certified copy of passport. I was to told this by a bank manager in Bangkok. They said if the branch won't do it, you can call corporate headquarters and they will make them do it. I followed her advise and got an account opened in Koh Toa, after being denied about a dozen times.