I have not heard of anyone doing it in CM. Not heard of agents helping with it here in any way. Must not be a market for it or not possible. Even in Pattaya the usual agents seem to be hands off too.
This is if you just need to show that your Telco Account is aligned to your passport and that passport to the bank account. It is a Bank of Thailand requirement for all mobile banking in Thailand - not just Bangkok Bank.
I had visited before but never thought about living here. Just over a year ago I came up on scouting mission. Four trips last year and then came up twice in January looking at houses and condo's and took one. Now deciding if will extend at the condo or get a house next year.