The sword that Neville pulled from the hat WAS the Griffindor's sword. The sword was Goblin made but paid for by wizards. Bill tells Harry that the goblins don't understand that distinction. The sword belonged at Hogwarts and was owned by Griffindors...
Hard question... A sword which could slay a lot of demons in one swipe or a sword to bring back the dead..... Well truthfully I'd like Sesshoumaru's b/c then if I'm in trouble it would act on it's own and save me like it did when Inuyasha used his sw...
Try ebay, If you do not see it know what a few months and it will show up