Using a multi entry tourist visa and extensions will get you the closest to what you want. On the end of the extension you border bounce for another 60 day stamp. You can do that like 4 times I think.
"Expedia Trick"... Expedia has free cancellation within 24 hours with 100% refund. Tickets to Rangoon, Myamar are like $50 USD from BKK. Book the flight. Print the documents. Cancel the ticket. Boom done.