that's just not true I've opened bank accounts on tourist visas and I know many other people who have also. I used to be in the real estate business in Phuket and all my clients were just tourists who bought property but they had no problems at all in opening residential bank accounts with online banking facilities.
yes I understand that. I walked off the street into Kasikorn with my passport and got a Thai residential savings account as I did with SCB and Kasikorn and not once in 15 years of having retirement extensions have I ever been asked whether it's a residential or non-residential account. In fact I currently use a foreign currency account from Krungsri with an address in Thailand to support funds for my Visa. So I don't understand why Scot is saying he could only get a non-residential account for his Visa.
if you go the lump sum route the only requirement is that you show a statement from a Thai Bank showing that amount of 800k over 3 months prior to the initial application. They don't ask where the money came from. It could come from overseas or indeed it could come from another Thai bank account.
what is your situation? You are living in Thailand on a retirement Visa so you need a bank account with your address in Thailand. It's very simple. What other situation would there be? I would also advise you to open an account with Kasikorn and you will be able to get a K-Bank virtual debit card.