Just being me, I would paint a fantasy mural. Something like there's this dragon with it's wings spread out and it looks like an overview of it's flight that takes up most of the wall and the only thing you detail is it's head. His neck fades into the main picture. The main picture's boundry being the outline of the dragon. The main picture would be this scenery of this castle on a hilltop with mountians in the background and shadows of dragons flying overhead. And the castle would be the main peice in the mural. It would be really detailed and freaking awesome! and you could put like a poem or quote somewhere on the outside of the dragon's outline, and it would be awesome! Anyways, that's what I would do.