Thanks for your comments, everyone. I will chill on the sensitivity issue. There was also a suggestion on another thread similar to what sbader2 was saying - that is, using more center channel speakers; the model suggested was the Athena C5, whcih is currently on sale on AA for 75 bones. Not too bad at all, definitely an option (though mounting the centers as rear speakers would be a pain, I'd imagine). The Infinity Primus series would seem to do the trick as well, but doesn't quite have the best characteristics compared to either the Athenas or the X-series...
After mulling all of this over, I'm actually now leaning towards eschewing a sub alltogether, getting a decent pair of fronts and maybe using three C5s to round out the system. Reason being, I'm not a believer in subwoofers being able to create a realistic soundstage, particularly for music applications in spaces with furniture obstruction issues, as in most NYC stuio apartments. Plus, having all those frequencies emanating from one place is bound to piss off my neighbor downstairs and the guy in the adjacent apartment with the crazy girlfriend.
Alternatively, the Yamaha YSP 1000, which one can find on ebay and audiogon for around 700-800 bucks, could be a solution because of the space saving design (would require a sub though...). But while I'm reasonably sure it'll perform ok for simulating surround for movies, I wonder how well it can actually perform in a 2-channel music scenario, considering that the phyisical separation is basically nil.
So then, I am off to do some in-person research.
PS: Arrested Development is an excellent show and Bob Loblaw has got to be one of the best character names in TV history.