Also if you had like, for instance, shutter shades. You want white or black ones? pay 20$ and have ONE color change. pay 20$ more and you get another one.
but with your forces,laxes,gradients,etc, make it like the untradeable shiai items, except w/o shiai. You win HOTM 3 months in a row, you get your 512 Head texture renamed to "Baphomet's 512x512 Head Texture" and the name itself changes to like blue or something to avoid confusion.
Also, if you had an entire set of renamed items, and you still wanted the achievement, you can make the items recognized by an unchangeable number ID.
Baphomet's Vampire Force has the same item ID as Vampire Force. They both have ID E577. Simple solution to a simple problem.