I opened a Bangkok Bank account in Patong 3 months ago on a tourist visa. All I needed was a letter from immigration (500bht) my passport and 6000 bht, which is mostly the insurance scam they tell you that you have to pay on a tourist visa. 500 baht and 199 baht of that 6000 baht were 500 to go in as account funds and 199 baht to pay for my ATM card.