I think that a scandoubler for good old video slot would be the right answer for most of all A4000D and A4000T users. One could complain about the loosing a zorro slot, but not forever if an half-size zorro board is fitted behind like the Deneb USB or controller for example. My hope is that a slot version of the Indivision could see the light because since from ScanDoubler II (that was a full size board so not very optimal) no other similar products have been released since.
Regards, CyberDez