If you have ever picked up an "Armor" magazine (the journal for all things armor for the army and Marine Corps) you have probably seen these prints. Many of the WWII ones are simply pencil drawings and look great. He has done some drawings for other eras as well; the most recent being "The Surge." Here is the one that made me think of Jeeper:
You can see the rest of his stuff at:
http://www.jodyharmon.com/militaryart/armor-gallery.html
Another great army-centric artist is James Dietz. He has been featured on many WWII magazine covers:
http://www.jamesdietz.com/gallery/merchant.ihtml
Finally, the Marine Corps has their resident artist as well - Col. Charles Waterhouse, ret.
One of my favorites:
"Farewell to Iwo Jima"