You can set this one in the "man, i'd spend my money on this" column:

Story:

As a player, I'd like to be able to quest or purchase a "skin" of a selected alternate character to apply to any cargo disc, so I can have my "alt" follow me about in the world.

Gherkin scenario:

GIVEN player has an alt skin in their inventory
WHEN player drops alt skin on a non-themed cargo disc
THEN apply the character model associated to the alt skin to the targeted cargo disc

Example:

I have a standard iron-slate cargo disc on my dragon.
I acquire the alt skin of my other character (a dryad).
I drop the alt skin on my iron-slate cargo disc.
My cargo disc now looks/moves like my alt character (dryad).

Possible implementations:

1. Create a technique that attaches the alt character's model to the item.
2. Create a socket that can be applied to the disc (skin only) and a crystal/gem that is associated with the model.
3. Create an "appearance" slot that will accept any appearance token and apply the associated model to the item.

General thoughts:

I had both of my characters running about crafting the other night when the thought occurred to me, "How cool would it be if I could have my disc take on the appearance of one of my alt characters?"

Then, it occurred to me that something like this could easily be expanded over time to include both disc, pet, and even character/player skins. (This is, of course, something I've been talking about and wanting since, well, forever.)

Your thoughts welcome!