We've started an official DeviantArt site for the book at where we'll be posting selected artwork from the book over the next several weeks. So feel free to take a look at animeangelsbook
And Red-Priest-Usada made a great publicity artwork for the book - here's the thumbnail image:
You can click the image to see the larger version. She has two artworks in the book, and this publicity art shows the initial lineart for one of them.
The Kickstarter page for book preorders is at this site