How many threads need to be made... JustG already stated they are not working on this at the moment, they have more important things to attend to for now, e.g. expansion, battlegrounds.
If anything, just release new vanity designs with this upcoming expansion... recolouring can't work for every vanity design. How does a red ice yeti/golem/spirit make sense? Is Frankenstein pink? Is a ghost rainbow coloured?