Hi LABs,
Difficult to do proposal if we don't have at least the decoding logic schematics.
If can probably be possible to do SBPro emulation by removing your filtering algorythm in Stereo mode. It will then have the same quality as the SBPro at minimum.
What I am waiting for are the support for SB16 Command (Signed DMA output) but you already know this.
Then, the use of CPLD is compatible with the "Do It yourself" spirit. Somebody wanting to spend time to build board can buy a cheap CPLD programmer and you can send them already programmed.
It will simplify the board a lot and add the possibility to do Tandy 1000, Covox, Disney, CMS with the possibility to decode more @