Chris, have you considered using some professional photography? High quality stock art is pretty cheap. I use a site called
Dreamstime. A single large photo costs as little as $1 to $10. And you could easily combine one photo of a model with a second photo for the background if you can't find a single perfect picture.
In the good old days, fantasy novels often featured beautiful hand-painted landscapes and portraits of scenes from the book. Today, with the growth of skilled costume-makers and makeup artists, photography is the faster and more cost-effective alternative.
Best of luck!