I personally think it'd be a solid move. The ability to "dye" our tamed pets either temporarily or permanently. I've seen different colored dragons on some of the free shards, and heck... Petsmart offers it IRL . Could set it up that the temporary dyes (available on NPC vendors for an exorbitant amount of gold) last until you stable the pet, Whereas the permanent ones (obtained as vet rewards or tokens from the UO store) will last until changed by another dye. Then you could also institute pet grooming on the stable keepers (also for an exorbitant amount of gold) where the pet needs to be stabled for a day to remove any permanent coloring before it can be dyed again.
Just my 2 cents.