Ok, 3 12's op? Really? I'm kidding. You need to understand that what you're trying to ultimately accomplish doesn't require quite so much horsepower. If you're just listening to music, virtually any speaker/system that is -3db around 30hz will supply those "flawless" lows you're looking for. I think you might be surprised what smaller speakers and a sub are capable of. Your best bet right now is to set aside the drawing board and go listen to every speaker and combination you can. Once you understand what you like, and why you like it, then you'll be on a much better track to ultimately design a speaker for your tastes. I used to want massive speakers with lots of drivers cause I thought it would work "better". I love the elaborate simplicity that smaller two-ways can provide. Stereo subs satisfy the bass needs I have.
Its ok to "want" to build something crazy. Trust me, I understand it. When I first heard a sub in a car, I wanted to rush out and buy 4 18's and a an 8gigawatt amp. Once I understood the process a bit more, a single 10 did just fine.
In the end, if you still want a massive 3 or 4 way design, then more power to ya, but you'll likely be thrilled with the "less is more" approach.