764
Some iPhone Duo screens are already failing
(arstechnica.com)
This is a most excellent place for technology news and articles.
And the G7 and G8 before the Velvet.
In fact LG was one of the few ones to try the dual screen phones. For them, it's via add-on cases. Then there's the Microsoft Surface phones. But then you have no choice because it's always attached. They're more like prototype current foldable phones though.