I discovered a new school in Chiang Mai that was recently opened by a reputable graduate from the Masters Program of Chiang Mai University. She has called the school The Easy Study Thai Language School. I understand that they are offering a terrific deal for a one year program which includes a one year education visa for about 20,000 Baht. This is a very attractive price and you can bet the price will eventually increase. If your into this, you cannot go wrong at this price. The teachers are supposed to be very good and all masters graduates. I think as a student you will receive good quality instruction here. Classes are 3 mostly 3 days per week which gives you plenty of time to enjoy life in Chiang Mai and surrounding areas.
Check out www.easystudythai.com. Good luck and enjoy!