Maybe you can summon a holy grenade to give to the pet? It may turn him a charred grey/black color!
Just thought I'd share some observations about MOB models in case you're interested.
Mobile OBjects (MOBs) in EQ utilize a system of bases and swappable textures. An alligator, for instance, utilizes its model's default texture -- a gray, scaly gator; swap to the next texture in the list and you get the little orange basilisk. This allows the client to save memory by having multiple textures share the same 3d model wireframe and animation set. (Think of it like old-school Mortal Kombat and its notorious "palette swapping" -- Sub-Zero, Reptile, and Scorpion were created by merely swapping the colors of their ninja uniforms.)
As far as playable races go:
Default texture = no armor (a.k.a. "cloth armor")
Second texture = leather armor
Third texture = chainmail
Fourth texture = platemail
(There are more beyond these, such as robe patterns and Velious racial armor for the pre-Luclin models.)
This is how shapeshifting Enchanters can get so much mileage out of only a few targets. Shapeshifting into a BAR BST's wolf pet will utilize the default texture, i.e. a gray wolf. Casting Illusionary Leather on himself beforehand, the Enchanter can then shapeshift using the same target and take the form of the wolf model's second texture, i.e. a black wolf. Chainmail (playable races' third texture) will yield a white wolf (the wolf model's third texture), and so on.
Some MOBs have only one texture, whereas others have half a dozen or more (think willowisps, spiders, dragons, etc.). Off the top of my head, here is a list of the current BST pet setup for BAR and OGR and the corresponding texture swaps to give you some idea:
Barbarian
Polar Bear -- Default Texture: Brown Bear, 2nd Texture: Black Bear, 3rd Texture: Polar Bear
Snow Wolf -- Default: Gray Wolf, 2nd: Black Wolf, 3rd: White Wolf, 4th: Jackal/Coyote
White Rabbit -- Default: White Rabbit
Ogre
Elephant -- Default Texture: Elephant, 2nd Texture: Woolly Mammoth
Gorilla -- Default Texture: Gorilla, 2nd Texture: Undead Gorilla
Skunk -- Default Texture: Skunk
As you can see, some of the BST pet models get a decent variety of textures, whereas others have only one. Unless Slaar & Co. were to do some more SoD-exclusive texture work like with the vine-covered hooded guys and green owlbears in OG, having an alternate appearance for the final BST pet just isn't viable across the board for all BST pet choices.