A great book for early fairy tale tellings is Jack Zipes' Beauty and the Beast. One of my favorite stories - as well as most inspirational, in the sense of writing my book - is Finette Cendron by Marie-Catherine d'Aulnoy.
A quick plot synopsis (and, let's face it, the title) makes it sound like a Cinderella retelling. And it is, but not at first. In the beginning of the story, the family has fallen from royalty to hard times, and they decide to get rid of the three kids (yep, three, just like Cinderella, but they're all sisters, not stepsisters). So the story goes all Hansel and Gretel, with the mother planning to abandon them in the forest. It even features a fairy godmother. But she's there to provide, not ballgowns, but a means to find the way back home. The story gets pleasantly wackier from there - the stepmother takes them, literally, 1000 miles away from home - on foot - and even further the next two times! And the fairy gives Finette a box of millions of diamonds, which seems to be of no help whatsoever, in relieving either their poverty or aiding them when their mother finally succeeds in losing them (on the other hand, they all fit in one box, so either it's a magic box or they're pretty tiny, worthless diamonds).
Eventually, the sisters find a house in the woods, which is not made of gingerbread, but of gold, diamonds, and pearls! More of a temptation to two very vain older sisters. But, as in all tempting houses in the middle of nowhere, there's trouble inside (a good lesson for anyone, in or out of a fairy tale). A giant ogre and his wife live there, who want to eat them all. Again, Gretel-style, Finette tricks the ogre into the oven, but there's still the wife to take care of. Which she does, with an axe. Finette is not a passive Cinderella.
From this point, it's more recognizably Cinderella, except there's no fairy godmother helping her out. No, it's a fairy clothes chest (Finette comes across a lot of magic boxes. Seeing my basement, I wish I had a few). And the story, of course, ends up with her marrying the prince.
As an aside, the prince is a big shoe guy, more so than the typical Cinderella prince. Sure, he danced with the lovely Finette at the ball, but the woman he really wants is the one who fits the shoe he found in the woods. When Finette comes to try it on, he doesn't say "It's you!" or anything, he just thinks to himself "She's so pretty I hope the shoe fits her." The guy likes shoes.
What I liked best about this is that it wasn't a mash-up, or a twisted tale - the author just used tale types (cannibal in the forest, Cinderella) to make her own story. This was back when fairy tales were first being written down! If she could do that, I figured I could too - I had all the story types, why not try writing a new one?