There is an artist called scott robertson who has drawn millions of thumbnails and even invites people to get ideas from them. His gallery is called "the drawthrough collection"
and is on the internet. he has made three books;
lift off (spaceships)
start your engines (cars)
Concept Design 1 (other artists pictures)
Concept Design 2
The Skillful Huntsman (futuristic grimms fary tales)
How to Draw Cars the Hot Wheels Way
They may not all have armour and weapons but are very interesting. They even have step to step guides on drawing most of the objects seen!
