My suggestion is a promo called Cupid's Wings, a white-colored elytra with a heart in the center. - When flying it leaves a trail of hearts behind it. - Enchantments would be Soulbound, Unbreaking V, and Final. - A 'broken' Cupid's Wings would then self repair after a 24-hour period. It would not self-repair until it is 'broken' nor while worn. How will this promo be obtained? Availability could be one of several ways. 1)- Thru the in-game store or it's future equivalent and be limited to one per Minecraft account and untradable afterwards. 2)- Limited-time uber-rare drop from EMC's special mob bosses, excluding Netherhounds due to their higher spawn rate. 3)- Voter's Streak 227. Those that have surpassed this would get it their next vote streak. In order to protect the current elytra market, firework-boosting with this promo should be made unavailable if possible.
Retexturing the Elytra is not possible unless done client-side with either modifications or resources packs. It's the sad truth, but those are the only ways. Though... there is a client-side mod that can do just that which is on the approved mods list: Capes Mod (#ShamelessAdvertizing ) Here's an image from Roslyn with a re-textured elytra for Halloween using the mod:
