For those interested in this question , here are some answers.
Vietnam RMIT Ho Chi Minh City
Vietnam doesn't have upper age limit for work visas. "I got a job at age 63"
(6/17/2011) I applied to a school in Vietnam which was interested in me UNTIL I told them my age (60). The Director told me Vietnam has strict age limits for teachers. This contradicts the previous post
(8/4/2014) The Vietnamese Embassy in London confirmed by email that there is no legislation relating to working age in Vietnam. Age restrictions are up to individual employers. I am not a teacher but a lawyer.
Are there any Native English teachers on this site still teaching past 60yrs?, ( legally ).