According to the Bangkok Post, the Thai launch of Windows Phone 7 was a success, with the only phone available — the HTC HD7 — selling out immediately. It went for 22,900 baht which comes to $760 more or less, with a 799 baht ($26.50) monthly data plan, though initial adopters get a 500 baht per moth discount for the first eight months.
Thailand is only the fifth nation to get WP7, and I believe the only one to use a non-Roman script. According to current reports, it is possible to type in Thai on the platform, but only using a special HTC app. We assume proper support for the language is coming with the other Asian scripts in the second half of next year.