Thai Airways do recruite other nationalities crew but only for interpreter and aviation requiremeent from the countries of its operating like Japanese, Chinese, Korean and a few fore country as I concern..
In 2007 they recruite Thai Crew (for 2008 Batch) around 200 of candidates success. However, due to the crisis they design to freeze around 100 candidates... so they are still waitng for the training.
I'm , as a crew (not with Thai Airways), I can say that Flight Attendant is one of the top 5 jobs in Thailand, each time any airlines open for the recruitement more than 3000 candidates will join the interview.. The chance of getting this job is very difficult..
If you live in Thailand, I suggest you to apply with Qatar, Emirates or Etihad when they open in Bangkok. But you may feel it is crazy many of Thais also go to Malaysia, Singapore even England for the recruitment...
have a look at www.thaicabincrew.com/forums
(but it's mostly in Thai)
I wish you the best to get Flight Attendant job....