I recall seeing an anon doing this weeks back and it interested me. However, before I go any further, should I include third versions of each game? I know Emerald is animated sprites, but the static model is the same as RS whereas Platinum/HGSS changed a ton of sprites. Black and White and their sequels had plenty of changes. GSC is tricky to me due to the color palette and brightness. Are they low in saturation or neon bright? I've visited various sites that have sprites of the Pokemon and wonder which is best? Also, which pokemon had sprite differences in Crystal?
serebii has the 3D models from XY
bulbapedia is organized with the sprites for each page
pkmn.net is great along with spriters resource.