I remember they used to make that visa in HCMC as well, when has it changed? Any difference in the requirements if the visa is based on a wife or on a child?
Thanks all for the answers, I'll write how it has gone in case someone interested.
It took 2 trips to immigration office to make them transfer my stamp, copies of every single page of my old passport, 1 trip to atm to withdraw 20k, fake air ticket, proof of address, wasted all morning just to get stamped out of Thailand.
Then the boat is 100-200 one way, stamp service in Myanmar 500.
Wanted to try once but I won't repeat and I'd advise against this option.