Here's the first volume of Battle Milk. It was published in 2008. Paperback, 80 pages. It's a bit thin but the work is pretty cool. The concept art is on characters, mechanical vehicles and background paintings.
Since I'm only seeing this book after I've reviewed Battle Milk 2, it does feel a bit underwhelming, relatively.
This book could be hard to find. The ISBN is 9781606438763.
You can check out more work at www.battlemilk.com.