My .02 is that LF-Z Electrified is absolutely a preview of the production RZ, just as many other "LF" concepts have previewed other production models. "RZ 450e" is already trademarked so we know that is coming and is a logical follow after this LF-Z concept.
R = midsize
Z = New in-between sedan/CUV bodystyle with the LF-
Z
RZ = midsize vehicle between ES and RX... voila, and as
@supra93 and
@Will1991 have pointed out, the LF-Z has a midsize footprint
So for Lexus nomenclature:
_C = coupe
_S = sedan
_Z = "raised wagon"
_T = Touring
_X = CUV/SUV
In shape, the CT and LF-Z or "RZ" could end up being sort of similar, but maybe CT was a "one and done" effort and Lexus has plans to build out a family of "_Z" vehicles between sedans and CUVs. I don't see any "RT" trademarks.