The thing to remember is that "EVERYTHING" has a life span, and if maintained correctly will last for a long time.
Nissan made this box as an experiment, i.e. Bugatti only made the Veyron to prove that it could be done, and as a result only fitted it to the V35 as it was costly to produce and equally costly to maintain, there are other versions of cvt boxes on the market that do effectively the same job but are cheaper to manufacture and maintain.
With that being said, it is a fantastic gearbox and with the right maintenance schedule in place, should last a fair amount of time.
ps. I am organising a group buy of oil for these.
http://www.skylinesaustralia.com/forums/V35-Gt8-t326611.html