Post 40 for WAR tanks? Wow your server must rock. On my server it's post jungles, NIN onry by about 99% of the populace.
I even had to disband an entire party I was building up because half the members were opposed to a WAR/NIN tanking, yet have of them partied with me before where I had to tank as a PUP/WAR.
As for PUP tank...no...past jungles (and well pretty much anyone can tank dunes-jungles, I did it as DRG and DRK no less.) PUP's can't tank. Armor comparable to a mage, with a bit more evasion, and guard skill, and sub-par HP doesn't make up for outright high def and good armor. As of now, PUP really can't be a tank till SE fixes us. And don't mention the puppet as a tank, my Valoredge took more damage in the citadel per hit then I did. >.>
But BLU/NIN worked out well in one party I had. Used spells to hold hate, and shadows to blink damage. Wasn't half bad. Now if only this was a party where refreash exsisted (was pre 40) then BLU/NIN could be a pretty good tank.