You liked Celestia so much so why the heck not?
I pictured Celestia as the artillery and Luna as the close combat specialist.
The blade infront of her is the Star, the one on her flank is the Lunar Sickle. To make things clear, none of these are to be wielded using ones mouth. There are no handles or hilts, just insanely sharp edges.
Why is the chest thing holding the Star? Answer: magic armor, it is part of the set bonus
Now she can use her magic on other things, such as throwing her sickle around.
But seriously, horn glow would have fudged things up, so I went with the lesser of four evils. The third option having it just hang there with no effects at all. The fourth... having her hair hold it?
Celestias in armor: fav.me/d5owicp fav.me/d5oc007
Twilight in armor: fav.me/d5rvwqq
Luna in armor - no weapons: fav.me/d5va00e
valio99999 made an awesome plushie! fav.me/d5u4s8l
Big thanks to the guys on the Minecraft Forums pony thread for the early feedback.
So what to do next?
Note: A few people seem to think I got/took some design ideas from the game League of Legends, this is NOT the case. Please don't assume I steal designs just because they look similar. If I ever borrow design ideas I will be sure to give credit where credit is due. Thanks!