If you think about it...it's unrealistic. If he's good enuf qB to lead ND to 4 NCs, there's no way he'd stick around for that 4th year.
I suppose, technically, there's a slim chance. If Weis can recruit enough studs on both sides of the ball in order to have a dominating defense & enuf skill players on offense that Clausen doesn't stand out as the sole source of production. But that would mean that there's a lot of hidden gems on campus at this point & the next few yrs will produce a class similar to Vinny Cerrato's last class.