Understood. You really should be able to open a Thai bank account. I had an account with Bangkok Bank also. I got to know the manager and some of the staff quite well. Shame I'm not there now.
mine was 3 years ago but if you have an O A visa it should still be simple. All the branches seem to do their own thing. Depends on who you see when you go into the branch. Go in, be polite and respectful.