Stef, Haven't been to Bangkok for a few years now and things have probably changed. I went every three months for over 10 years to buy plane tickets as they were a quarter of the price in Japan. In Bangkok I always went first to see Nim and have lunch, from the alley behind the shop, with her at Prayer Gallery. Have known her for over 20 yrs and recommend her shop. If you stop in tell her hi from MAC.
River City used to have a lot of antique textiles and it was a nice ride on a river ferry from where I stayed. Has anyone mentioned the weekend market? Sat. and Sun. ask anyone as it is known by all. There you will find everything under the sun including textiles. It is a fun Saturday! Go at the crack of dawn, as the good stuff sells quick and though things are much cheaper than in shops you need to bargain hard!! That is part of the fun!
Do make the trip up to Chiang Mai as it is a cool relief from Bangkok heat and crowding and you will find textiles from all over. Ah, wish I were headed that way too!!! Have a nice trip

MAC