Yeah, it's been leaked and added to a custom ROM already.
Working really, really well on my M8. Absolutely love it. Google have really come through with the goods in Lollipop!
More info [Only registered and activated users can see links. ].
Credit to HolyAngel @ XDA for cooking it up with SkyDragon. Great ROM! Just flash how you normally would.
Won't be long now til a M7 flavour appears either I shouldn't think.
[Only registered and activated users can see links. ]