It would be nice, but I don't think they exist.
DLC/Free Update idea, gamesas... one dev, probably half a day's worth of work, just copy the legendary qualities onto the armor pieces and add a custom script to ensure it only works on enemies wearing PA...
... Mmm, then again, it might only attach to the frames, with the legendary enemy rolling its equipment independently of the frame. That might be a bigger change.
only ones I've seen are from quest rewards, no drops.
Well, there's a unique arm piece from a raider, and you can find a unique chest piece for power armor in a research lab.
Well, I now have 2 legendary chests, and 0 other power armor pieces. It annoys me in that, no matter what, 1 will not be used by me. It would have been nice is after a 100% playthrough, you could end up with a full legendary set made of mismatched legendary pieces.
Fixed drops only, AFAIK.
Wish they weren't. That would be very neat.
There is Visionary's T-60 Helm (mission reward), Exemplar's T-60 Torso (mission reward), Honor (BoS vendor and Paladin rank), and Vengeance (BoS vendor and Sentinel rank). All of these items are Legendary BoS Power Armor equipment. Only the Left Arm doesn't have a unique Armor.
I've never seen a legendary/unique power armor drop. I've gotten several of the scripted pieces as quest rewards, but that's it.
Only Tessa's Fist is a unique power armor drop since it drops from a specific Raider that can only be found in a specific location.
Oh yeah, I forgot about that one. I've never even used it before, but I've had it for a long time.
You would think so with a name like that, but it is the only unique Raider Power Armor in the game. Even then, it is not considered as a piece of unique equipment due to having no star since it doesn't give a unique bonus like every other unique equipment just an increase in its durability stat.
Even if it were as say rare as a leg. gauss gun, I'd be very keen for added Leg. PA drops to be included at some point.