The TMC 16/0 thread was manufactured at a factory in Thailand. I got the guys at The Spot and Bob Marriott's to stock it after it came out. When I became aware that it was being discontinued, I grabbed every last of spool that Marriott's had...You might want to contact Tiemco directly, in Japan and see if they can steer you to the original manufacturing plant in Thailand...I have enough left to last for awhile...
This is Tiemco's Japanese site. *Note that they are still in the biz of making fly tying materials:
Hope you can get them to put you in the right direction. Semper-Fli 18/0 Nano Silk is OK as an option, but it lacks the characteristics that made tiers like Charlie Craven and Juan Ramirez rave about Tiemco 16/0 for the little guys...See you on the water, my friend !