As I understand, NO agent can do it, anyone dare, they will arrest them.
Go to immigration, tell them you are applying for a visa ( pick one that you will qualify for and require bank account balance) Ask them for a letter of permission,
If you are inside the country, there are other visa you can apply, go to immigration, ask for a letter of permission to open account, base on your application visa type that requires account balance. Then go to Bangkok Bank.
Well, if you want, go to Huahin, I will give you a contact to help you do it, she is an agent, she is very good and has contact in Immigration. And most importantly, she is very honest.
let just say, you grow what you grow and you don't grow it to sale, does that call a "JOB"? or you do just to follow order of your wife or to kill time?