Before I recently offered all the villain bottles at an auction I put them all up for a a last picture. It turned out that the bottle I had picked for Sombra was smaller than all of the other bottles (it was not a deliberate snide against him ;)).  
In the end the bottles weren’t sold on that occasion so future projects with more than one of them are not excluded. If I come by further Baileys bottles (a bit of a challenge since I hardly drink any alcohol myself) I may do a regular size one of Sombra or one of the Pony of Shadows (which had kind of replaced Sombra as the most underused villain given the major buildup set against the very short villain carrer), or maybe one of Discord and there are more possibilities. It appears the villains (and reformed villains) of Equestria require more bottles to be emptied. I do hope some of my friends will assist me in getting Baileys bottles emptied for this purpose :D