So, I read that book, "Twilight Sparkle and the Crystal Heart Spell." Super adorable and full of puns. But aside from every single punning opportunity being taken, it briefly talks about how Cadance became an alicorn. It was super duper short, all of 2 pages in the gigantic font that kids books use, but still! It was way more than we had before. Her story may be thrown our the window by some later episode, but until then, I'm satisfied to accept it as temporary canon.
Brief summary for those who will never bother reading it:
Cadance was a pegasus baby who was found in woods and taken in and raised by earth ponies. She filled others with warmth and the "urge to protect her" (wtf, really? boooooo.....) by the natural love and compassion she held for everypony. An evil pony enchantress (who, I can only assume, did evil pony dances, and put others in evil pony trances), named Prismia, used her prized possession, a mini crystal heart like necklace, to leech the love out of all the villagers. Cadance sure does have a lot of run-ins with love leeches... So that necklace also amplified Cadance's love and defeated the baddy by, I can only guess, overloaded the crystal and reversed the spell on Prismia. That's what i got from it, at least. When Prismia changed her ways, Cadance got transported to that glowy, alicorn-making realm, "a place that nopony except Princess Celestia had ever been!" Poor Luna always gets forgotten... or got alicorned some other way. It says Celestia discovered Cadance there and took her to be her royal niece and live in Canterlot. It goes on a little more about how she attended Celestia's school, solved a whole bunch of conflicts and helped ponies find love, despite not finding love for herself (sans a crush on Shining Armor).
Anyway, its a really inexpensive book that can be read in an hour or two, so go read it.
So, this is that moment of Celestia finding Cadance in the alicornication realm. New style, just trying something different.
Edit: Eqd'd [link]
I forgot that awesome feeling of having my shit volunteered by random strangers. All of the possibilities with none of the potential rejection.