A while back I had found an ASIO driver designed specifically for running DAW software in classic mode on OS X.
It was a strange beast and it did actually work with Cubase (that was all I tried it with).
So it was an ASIO driver you would use with whatever classic app you had and it routed directly to the OS X core audio. It did not just redirect to the Sound Manager in classic. It was only stereo output, no input and due to the nature of OS X and classic, the performance of the DAW was not great.
I can't find anything on this any more. Does anyone else know anything about this?