Look at the Lazada.co.th website and change the language to English..Look at bikes..folding bikes..and on page 5 ..each page showing about 28 bikes you will see a Brompton Clone for 12500 Thai Baht..Lazada are like a Thai Amazon or Chinese Alibaba..
I think you would have to live in Thailand to order one..or a hotel I guess..
I have seen them in the Worachak road area of Bangkok..there are about 10 bike shops in the space of 200 yards..near Wat Saket(Golden Mount Temple)..and I am certain they are in plenty of other shops also..