It's problematic. For one, it would be a male only item since there is no female version.
Furthermore, there's 2 3D robe models (Jedi and Master) for players/party members, you can't really* have only one item use another model.
* You can use the Revan/Starforge robe model "slot" to use a new 3D model, but you can then only use one mod that does that. You also need to fix Atton's entries for this "slot" (columns in appearance.2da) because he doesn't have any values there, which causes a crash if he tries to equip the item. All in all, tricky business.