That Bidule is not something I'd be using in a mission-critical project, but good to know there is a workaround.
Like I said, Steinberg supports (or used to support) Direct-X plugins on Windows, and MOTU's Performer supports AU in addition to their own proprietary MAS system.
I can understand Steinberg is not going to adopt competing standards like AAX or MAS, but AudioUnits is a different story. Like CoreAudio and CoreMIDI, it is part of the operating system, not part of a competing product. Cubase uses CoreAudio/MIDI, so why exclude AudioUnits?