I have thought about this a lot and have come to the conclusion that in the year 3302 that a computer controlled device like a scanner wouldnt take up a cargo bay. All ships should have a basic scanner system around its body as standard, but the strength is controlled by the type of "card" used on the motherboard; much like your graphics card can be upgraded to give better graphics today.
So i think if ships have a "motherboard" with varying slots available dependant on ship size, or even an upgradeable motherboard, then each slot can have whichever card can go in it i.e. an ADS, a DSS, KWS, Wake Scanner, DC etc.
This way the bigger ships can devote cargo bays to cargo etc and not sacrifice a slot 4 for a class 1 DC or scanner.
So i think if ships have a "motherboard" with varying slots available dependant on ship size, or even an upgradeable motherboard, then each slot can have whichever card can go in it i.e. an ADS, a DSS, KWS, Wake Scanner, DC etc.
This way the bigger ships can devote cargo bays to cargo etc and not sacrifice a slot 4 for a class 1 DC or scanner.