So I did reach out to Nakamichi by email, but then I believe I found the answer on the website, in the description of the Ultra 7.2 Shockwave (as opposed to the earlier, Pro model). If the 9.2 and 7.2 models are the same in most respects (except the 9.2 doubles the satellites, and permits coupling them as dipoles), the rear speakers are wired to the rear subwoofer. If this is true… I'll know when I get an email from them… then it seems like an acceptable compromise in what looks to be a very powerful, and fairly priced sound bar.
Also, in their description, Nakamichi talks about object based sound that can place sound anywhere in the room, and so it's probable that the soundbar includes DTS Virtual X. As I mentioned before, the side firing tweeters in the bar itself are angled slightly upwards. This contrasts with the Creative bar's four up firing drivers in their bar. But the Nakamichi 9.2 also has true rear (and side if you prefer) for actual discrete channels. I'm really curious to see a review of this soundbar.