I am currently in Bangkok for two days (not of my own free will), and, visiting Panthip Plaza, I found That’s 4x DVD+R available at a few stalls – this is Taiyo Yuden manufactured.
The sellers told me that there is a distributor who is experimenting to see if there is a market in Thailand for these disks. They currently cost 200 baht each (about US$5). with no volume discount.
So anyone in or passing through Bangkok who is interested in these (expensive ) TY DVD+Rs should look around at Panthip.
Incidently, they have plenty of TDK 4x DVD+R (Ricoh/Ritek, I believe, made in Taiwan), but no TDK 4x DVD-R disks (ie. TY disks branded as TDK).