So it happened finally...
Auria - first professional DAW for iPad updated with Audiobus.
Auria full version was submitted by WaveMachine Labs. but not yet approved by Apple (it should happen very soon - maybe in just few hours).
As Auria is memory consuming app it recomended to run it with Audiobus on iPad 3 (new iPad) or 4th generation.
Also there's an issue with buffer size so you should first run Audiobus and only after that launch Auria. Read this Audiobus blog article.
Want to know more about Auria and other DAWs for iPad will support Audiobus - read this review.