Has it occurred to anyone that the different looks needn't actually be separate sprites? All they'd really need to do would be to have a base sprite, a set of quirks for each (say, a pattern of spots, tufts of hair, different eye shapes etc., all overlayed onto the base sprite) and then an algorithm based on IVs that determine:
- Whether or not the quirk is visible on the base sprite at all
- Positioning of the quirk with respect to the base sprite
- Size of the quirk
It'd basically be the same thing as they did with Spinda back in RSE. There aren't 65,000 different Spinda sprites on the RSE cartridges. Rather, there is a single Spinda sprite and each Spinda's pattern of spots is procedurally generated from its IVs (and possibly capture data) every single time that particular Spinda's sprite is displayed.
The beauty of it is that since the IV data remains constant for each monster, the individual look will always be the same, even if the monster was traded over from another game. An added bonus is that since IVs are partly inherited, certain quirks can be passed down the family line.
Some smart people over there have thought of this or things like it.