LABS wrote on 2021-07-21, 17:15:
There is already an Orpheus available and AWE64 Legacy on its way (?), so I don't think there will be enough interest.
There is no currently-available card that offers all of those features, though, and certainly not one built exclusively from new, readily-available parts. Orpheus offers better Sound Blaster Pro compatibility than the Sound Blaster 16 ASP (or later), but isn't Sound Blaster 16-compatible. Any descendant of the Sound Blaster 16 (including the AWE 64 Legacy) does not offer complete Sound Blaster Pro compatibility, and may have problems with certain other DSP commands.
If you can deliver on that feature set, while still having respectable MPU-401 compatibility, I suspect the interest will materialise. Of course, no one other than you can decide if that potential interest will sufficiently compensate for the effort, cost and development time that would be required to make sure that such a design is mature enough to ship to paying customers.