Subdoofus,
Ric Schultz's site says that their "Ultimate Attenuators" have been temporarily discontinued. No news when they will begin making them again.
As for "high-quality" passives, the best that come to mind are the Placette, FT Audio, Morrison ELAD, and Belles has the GR-8. You could start a fairly ugly fistfight between owners of the first three as to which is best, all have a very dedicated/fanatical following. I don't think many people have ever really had two of them in their house at the same time, so opinions are highly subjective. But, most of them have stopped looking after plugging one into their system. Like anything in this hobby, it's a matter of personal taste.
I haven't heard much about the Belles, it's fairly new, but their amps are highly regarded and I doubt they would squander their reputation at this point.