Can't help with finding one, but those RD60 tanks are cool looking items. Perfect for mini race bikes. A buddy of mine is going to let me borrow his so I can see if it fits, looks right on my F11 cafe I'm building.
If still needed I have a serviceable at minimum and possibly excellent light metallic green CB200 tank with petcock if I remember correctly though it does not have the black plastic strap or stripe depending on what you want to call it. If you are interested I will go pull it out and get you a better description and photos. kevin at nixoid d0t c0m