I'm still restoring the pool, which'll take another couple of days (no word yet from Gillware), but I got off my duff and took the Sabrent apart. I have to say that it's really impressive on the inside, with almost everything some manner of metal. Only the front doors and a handful of other parts are plastic. Unpopulated, Sabrent says that it weighs 17.8 lbs, so it would definitely kill you if someone dropped it on your head, even drive-less.
The PSU is a very cute 3.5" x 5" x 1.25" device that should be up to the task since it only has to have enough oomph for 10 drives along with the two 120mm "Runda" RS1225L 12L fans. As you can see from the label, it's a 399.6W "Mean Well" EPP-400-12 unit when cooled adequately. Since a normal 3.5 drive only consumes around 9.5W at load, that's only 95W needed for the drives, with the rest for the fans and the supporting PCB.
So, assuming the PSU isn't outright lying, I don't think that's the issue. I checked mine for obvious problems, like expanding or leaking caps, but didn't see anything. The caps themselves look to be of pretty decent quality and the bottom circuit board appears clean. The unit has what looks to be a rheostat, but I have no idea what it controls.
If I had to take a very wild guess, I would say there's something amiss with the backplane, as that seems to be a common source of consternation with low(er)-grade server-style boxes, like the Norco. It is interesting that I only started seeing drive dropouts once I had populated all ten bays, so maybe it works fine with only 8 or 9 bays running.
So far, the two Terras are running just fine. I'm praying to all sorts of gods that it remains so.