As you want to travel..then take yourself to Thailand and there you can buy a replica 3 speed Brompton in aluminium with fenders and a rack for roughly $350 ..You can order them thru the Lazada website online in Thailand or you can go to Worachak road and you will find some bike shops who sell them..You could get most of the other minimilast kit in Bangkok ..ie..a Vincinta carry bag for your Brompton clone..etc etc..or someone could make it for you..
Or look on the Lazada website anyway and you will find dozens on folding bikes..and they will deliver them to your hotel /address in Thailand..