Book Cover Art for a Children's Book

The story is The Mattress Stairs. The physical book will be 197mm x 132mm (portrait). I'd like the cover to be extended onto the back cover as well...so overall dimensions are 164 wide x 197 deep. I suggest art that reflects the title (and the key moment near the beginning of the story where the young boy jumps down a lot of floating mattresses that are suspended in mid air). The boy is never properly described so he needs to be silhouette or implied. Art style has to be not cartoonish. And because there are minimal elements you will be need to really good at illustrating empty spaces - absolutely no gradients, no solid fills. Although it's dark you've got to fill the darkness with something 'textured' or patterned. I can provide a rough diagram of what I had in mind. I only require the drawing - I will add type etc myself.