Anthony, ya, the current woofer can do it sealed and I personally use this woofer sealed in my HT. however, it doesn't win any awards for its bass response. Sealed it rolls off starting around 100hz, so 80hz isn't an issue, but don't expect pounding bass at 60hz from it unless going ported 2cuft. Also, yes there are other 10" woofers I have my eye on for a higher end TM. There's a lot of people who are scared of 12" woofers playing 1200hz content. So a high end 10" is on its way. But right now its simply a concept. The TM using the delta 10 is actually in progress and will be available sooner than an Alpha design.
Bob, glad you found the thread. The separate mids do help with vocal range clarity IMO. It also helps to break up the floor and ceiling reflections, which helps preserve vocals. The design is very flexible and I've listened to it as a center. It works nicely that way. Propping it up on a stand is tricky though. Particularly when its in three separate cabs the way I have it.
Pbc, I like the idea. Wanna build it