I always consider Donkey Kong a part of the same IP as Mario, and of course he hasn't had a big game in a while. Smash Bros. is bigger too, but it's sort of a mix of IP's...
Animal Crossing is 'core' in one sense of the word, but I don't think it is in the sense we're thinking of.
Metroid is not that big an IP really, but it's one of the more development intensive series on Nintendo consoles these days, that's why I consider it a 'big game', the costs to make it rather than just the sales it receives.
A game I'm developing with some friends:
www.xnagg.com/zombieasteroids/publish.htm
It is largely a technical exercise but feedback is appreciated.