Just in case someone else needs this info, there are 4 shops in the MBC in Bangkok. Two of them (on the 1st floor) have some used analog equipment, but I wasn't at all impressed with the condition they were in and the prices were significantly worse than KEH. For those of you interested in the D-word, there is a huge store specializing in high-end D equipment on the 4th floor if I recall correctly. Thanks for everyone's help.
For anyone thinking about taking a similar trip, Bangkok was very interesting, the markets make for great photo ops. Also went to Chiang Mai for some temple-hopping (bring fast film, I didn't have as much as I would have liked). Also went to Cambodia. You could make a career out of photographing the temples at Angkor Wat, just amazing. Finally returned to Thailand, in the Krabi area. Nicest beaches I've ever seen. Incredible seascapes and the clouds always seem to cooperate. This last one is highly highly recommended.