I have a 2002 that had the rusty hatch. It was not isolated to 2000.
I called corporate Nissan and went to the dealership. Major pain in the ass. At the end I had a brand new hatch instlled and painted. Paint doesn't really match but they tried 3 times to make it match so I gave up !
POINT.... call Nissan corporate and don't stop calling them till they fix it (assuming you are sure your paint warrenty is unlimited milage?)