Thrond

@Number62 According to what I've seen online, there's a chapter book where Cadance references having been raised by a village of earth ponies who found her in the woods. Obviously this is B-canon but it's an interesting enough idea that I'd like to see it explored in the show proper, or at least in a comic. 

This book also states that Cadance was a pegasus before becoming an alicorn. 

I'm not against tie-ins expanding on the show. The problems is that, as you said, they might not even be canon. And then I wonder if the producers/writers/etc. actually put much thought into this kind of stuff.

I'm taking it as canon until proven otherwise!