There are plenty of CIEM demo universals with 6, 8, etc. drivers. In that case, I heard two different ten driver universals before!
The S-EM6 is the first purpose-built universal that has 6 BAs. At the same time, however, it doesn't seem all that innovative. It's basically just an EM6 shoehorned to output through a tiny little 2mm tube. Sure, the manifold should be plenty complex, but I'd still say that something like a TO GO! 334 has more complex construction and pushed the limits of construction more.