I vageuly remember a story within the last few years where a farrrang ran into this when they sold the condo they were in. The bank deemed it to be a supicious amount and would not release the funds. That ring a bell for anyone else. Man you have to be careful here.
c. Currency Regulations 1) Foreign Currency
Foreign currencies can be brought into Thailand without limit. Any person receiving foreign currencies from abroad is required to sell such foreign currencies to an authorized financial institution or to deposit them in a foreign currency account with an authorized financial institution within 360 days from receipt, except foreigners temporarily staying in Thailand for not more than three months, foreign embassies, and international organizations.
Foreign exchange purchase or hedging with authorized financial institutions is generally available where a genuine underlying current or capital transaction exists.
2) Local Currency
There is no restriction on the amount of Baht that may be brought into the country. A person travelling to Thailand's bordering countries including Vietnam is allowed to take out Baht up to 500,000 Baht and to other country up to 50,000 Baht respectively without authorization.