Referencing:
http://www.nissanpartsdeal.com/parts/nissan-bushg-eng-mount~11345-n3000.html
Z Car Depot appears to have the transmission crossmember mount bushings...is that what you're looking for?
https://zcardepot.com/driveline/transmission/transmission-crossmember-poly-mount-bushings.html?search=transmission+bushing