I was mostly joking with the Heliand suggestion (but who knows? Maybe someone has done or could do a picture book version of it? That would be...different, lol.)
Of course you want to do market research to see where your concept fits into the existing shelf of comparable works, but the the suggestion to examine fractured fairy tales is not a bad idea. I don't think there are a ton of books like what you are suggesting, even though the fractured fairy tales are fairly well received. This could be a good opportunity to stand out.