You may also want to check out The Book of Lost Things by John Connolly. It’s about a boy trying to deal with the loss of his mother, his father’s new wife and the son they have together, and adventures he has with “stories that are real”. The main antagonist is based on Rumpelstiltskin.
Other Books I’ve read and suggest, just to get them all out of the way:
The Stolen Child by Keith Donohue – described as a modern day fairy tale based on the poem of the same name written by William Butler Yeats.
The Child Thief by Brom – a darkly illustrated retelling of Peter Pan and The Lost Boys
Faerie Tale by Raymond Feist – a modern dark fantasy novel of fairies and changelings
As you can see, I have an avid interest in stories regarding changeling children, thus I await
Some Kind of Fairy Tale by Graham Joyce which is being released in July.