In the meantime, unless you're in Canada, let me suggest the Franchi SPAS-12 as the ultimate home-defense gun (even if it'll run you a ridiculous amount of money). Not only can you rack the first round into the chamber with that sound that should turn even the most hardened home invader's bowels to tapioca, but you can fold the stock (shorter; handier), and then, should things get ugly, you can fire it semi-automatically without pausing to rack the slide between shots (effective rate of fire is about four rounds a second).

UPDATE: The Puter mentions staggering loads. For home-defense, load your first round with rock salt, the second with magnum double-ought buckshot.