Past a field where cattle still graze, about 13 miles from Fort Worth's vibrant Sundance Square, behind a guarded perimeter fence and a sprawling parking lot, huge machines groan and hum, churning out what may be the world's most coveted item. The product? Money. Greenbacks. Cold, hard cash. And it's here, in a high-tech Cowtown factory — not Washington, D.C. — that ...