On this note, while I was digging around, I found this from
2002 about their "GBL" (Global Body Line) which is an improvement from "FBL" (Flexible Body Line):
Toyota Adopts New Flexible Assembly System.
"To add salt to the wounds of auto makers that still see Toyota's old FBL as the bogey, Don Jackson, vice president-manufacturing for TMMK, calls the outgoing process “antique” in comparison with GBL.
...
(FBL-equipped plants could handle as many as five different models...
GBL-ready plants now can build as many as eight, rather than five with the FBL system.
...
Even with the ability to produce eight different models, there is a limit to GBL's flexibility. Once pressed, engineers admit that not everything Toyota makes, from Vitz to Land Cruiser, can be produced on a single GBL line. There are two sizes, one for small and medium vehicles, one to accommodate anything larger."