Mastery Skins

With the new Mastery levels 6 and 7, I feel like there should be an special reward for anyone who reaches these levels with their favorite champions. And there probably is one! In a other Moba game there are special skins for mastery levels, wich still need to be purchased with ingame or real life currency, though are only aviable when you master that specific hero for it. So I wonder, would it be possible to create skins like these for the mastery system? They don't need to be new and fancy, and could still have the old particles just recolored to fit the specific sheme the new 'mastery skins' would have.

it's just a suggestion but I had this idea for a while in my head.