I think you've covered just about everyone who's deemed "important." Here are a couple more for now.

Taiwanese filmmaker Edward Yang (A Brighter Summer Day) doesn't get as much print due to 2 obvious reasons (Hou and Tsai).

Apichatpong Weerasethakul (Mysterious Objects At Noon/Blissfully Yours/Tropical Malady) and Pen-ek-Ratanaruang (6ixtynin9/Last Life in the Universe) have made some wonderful films out of Thailand.