technically, it's possible to have 2 of the same rare item in your inventory. i remember checking a GM who was rehearsing a wedding ceremony in bastok and he was wearing a PAIR of bastokan rings. as such, i assume that if the method that adds the item to your inventory does not check for the rare flag properly, it might be possible to hold multiple. a gaff such as scripting
Code:
if(!PosessesItem(Memoirs))
{TakeMarble();
GiveMemoirs();}
without the brackets would logically give the memoirs to someone who already has one without taking the marble, thus permitting a player to get an endless supply of memoirs if he starts by possessing one. obviously, this is a stretch to rationalize, but i wouldn't say it's impossible.