I know Accugroove has a 21 sub cabinet out now. One of those, or heaven preventing-two of those plus a 4x10 with a decent tweeter would probably be enough to move serious earth.
If you are like me, I'd love to have this capability in a box measuring 15x12x18 tall-with 120 dbl efficiency and 22 lbs weight. Did I mention concert hall volume levels?
It's tough. Keeping in mind the more complex your system is, the greater risk for malfunction. In the big picture, the audience in the end hears your bass through the PA from your DI out anyway. So, there is something to be said for simplicity, component quality and an ally at the sound board.
My home stereo speakers are planar flat panels. They are about an inch thick, and around 5 feet tall. Sound quality is jaw dropping, but in no way suitable for bass guitar sound pressure levels. My point is that there is an application at about every level in audio. For now, Acme, Bergantino, EA, Eden, Bag End, Ampeg etc. are making great cabs. There is a subtle difference in each, and what sounds best to the user is the best way to go. Unfortunately, depending on your needs, size may be an issue in the end. For me, I've tried almost all, including making my own cabinets ranging from 2x10's to giant 15 folded horn bass bins. I bought and sold Bag End cabinets, only to come back to buying them again. They don't reach as low as some, but in the end, they are the most musical of the cabinets I've used. I'd say the Acme cabs are nice, too.
Forums like this are great, as it helps educate the buyer! No doubt, speakers are important. It's the way we immediately hear ourselves, so the most accurate product to our ear is what we should use. Only you can be the judge. Now I wanna go play bass. See ya-
Bryant