Taken from the Nissan USA search engine:
**** SMITH NISSAN, SC
JN1AZ4EH1FM440247
CENTRAL VALLEY NISSAN, CA
JN1AZ4EH3FM440394
ANDERSON NISSAN, AZ
JN1AZ4EHXFM440215
GARDENA NISSAN, CA
JN1AZ4EHXFM440263
Of the two sites that bothered making a page, neither have actual photos of the cars: just stock pictures at best. Not sure if that's tardiness or because they're still waiting for the Z's to show up (i.e. preorders).
In any case: they're in the wild (or going to be). Good hunting for those seeking one.