The truth is i know a lot more about bitcoin than i do peercoin. So im really moving out of my comfort zone here. I'm really not sure if a hybrid model is more secure. It is my understanding that POW was used to get a reasonably homogeneous and fair initial distribution of currency and that the ultimate goal for peercoin is to eventually phase out POW entirely. Peercoin sort of relies on the idea that anyone who controls a large stake will have more to lose from a doublespend than to gain since the doublespend would reduce the value of his stake and anyone who controls a small stake will not be able to produce more than a single block at a time. Still I see some problems with this idea. What if the owner used his stake to buy a put option right after the doublespend? what if he is even more heavily invested in an alternative currency that would absorb a large portion of the capital exodus from peercoin? what if he can liquidate his stake before news spreads of the doublespend? If however peercoins security model is fundamentally sound than you should be able to get pretty fast and secure confirmations.

there would be no way to determine whether two block authors were actually the same person.

i have been thinking about this a lot and i do think i have solved the problem of waiting for secure confirmations but its rather complicated to explain here. I made a thread about it but there were some problems in my initial outline. problems that i now think i have solved. maybe ill go back and try to update this thread to reflect that fact.