Warning: I will be uploading a lot of sketches of "Fakemon."
The only name I could come up with that I even remotely liked was Cirruseon.
How to obtain: There would be a new, rare to catch wing called the "light wing." You'd make your Eevee hold the light wing and level it up. It will evolve when it is happy enough AND holding this wing. Therefore, instead of an Espeon/Umbreon, you get a Cirruseon because it is holding that wing.