FWIW, the Princes of the Apocalypse (OFFICIAL!) adventure has a black dragon shapeshifted as a drow lady-of-the-manor the PC's must negotiate with. I take this as license, as a DM, to give evil dragons whatever powers I need to make them bad-



NPC's.
This was already discussed - it is an illusion, not actual shapechanging.
So regarding shape changing chromatics what we have so far is:
AD&D: dragon #50, pg 12, any dragon over 401 yrs old can shapechange
AD&D: Ember the red dragon could shapechange (dragonlance), -
polymorph self per DL2, pg 25
3e/3.5e: Any dragon in Eberon can shapechange (with the right training), Dragons of Eberon, pg 15
3e/3.5: Black dragons can cast shapehange on Krynn (per the Black Dragon Codex)
3e/3.5: Monster Manual half dragons occur when a dragon changes its shape and mates with another creature, includes offspring info for all chromatics, pg 165?
3e/3.5: War of the Lance, pg 251 - Embers 3.5 stats: "Ember has the ability to polymorph himself into human form" Interestingly
polymorph is not listed as one of his spells in this edition, so this must be an innate ability.
4e: Draconomicon II, reference to chromatics having the ability to shapechange.
5e: Shadow dragon - not chromatic, but could be evil
5e: Shadow black dragon - cast illusions, but doesn't shape change
5e: Half dragons are created from polymorphed dragons mating with other creatures (one 3 possible origins). It specifaclly mentions half-white and half-green offspring, and provides an example of a half-red
Did I miss anything?