I hope this wouldn't be too challenging to code, but my premise is:
1) Player purchases a "beholder eye elixir" (placeholder name) for a modicum of Turbine points (i.e. 150-200)
2) Placed in the Stone of Change with a single item, either torso slot or hand slot, a successful transformation will destroy the item and the essence to create a "beholder essence of [base item]" (placeholder name)
3) Player can apply the essence to an item of the same base item type the way an armor kit can be applied to armor
Armor example: PlayerX wants to conceal the fact that she's wearing Spidersilk Robes like so many other characters of her level. She places a beholder eye elixir she has purchased in the stone of change with a loot-generated yellow robe whose aesthetics she appreciates. Because the Spidersilk Robes are an appropriate base item for her newly-created "beholder essence of robes," she can apply that skin to her Spidersilk Robes and toggle them on or off at her will.
Weapon example: PlayerY wields a greensteel scimitar often and the graphics do not appeal to him. He creates a beholder essence of long swords and attempts to apply it to his scimitar, and it fails. Realizing his mistake, he obtains a scimitar whose graphics are appealing and applies those instead.
Logic: the customization from armor skins and cosmetic helms has undoubtedly given a boost to Turbine's revenue, and adding items of this nature in the Turbine store (and occasionally as rare drops in quests to whet players' appetites for more customization) would fill the gap for players that really want to customize their look outside of the pre-made armor kits.
It gives players a way to pay Turbine for a comparatively limitless amount of customization decisions, so both parties benefit.
Other people may have come up with this idea in the past (a cursory Google search didn't help me find it, however), but I would personally pay Turbine points to mask/change the graphics of many items on even more characters, including: Minos Legens, Sword of Shadows, alchemical quarterstaves, alchemical light shields, all named armors, greensteel khopeshes, greensteel quarterstaves, and more. A lot more, in fact.
If it is easier on Turbine, perhaps releasing only armor aesthetic deconstruction initially and then piloting weapon aesthetic deconstruction might be easier.
The technology already exists for applying skins, and I think the entire community could benefit a lot from being able to roleplay their characters, distinguish themselves, and spice up loot generated equipment finds.
With the amount of ninja cowl+spiderspun caparison or gold skull helm+gold spiral armor kit combinations I see running around Sarlona, I've no doubt the playerbase would capitalize on a new resource like this.
Cheers.