Flint is one of the new macho names on the rise today, part old-school tough guy, part rebel. You won't find a tougher, steelier-sounding name; it's part of a genre on the rise along with cousins Slate, Stone and Steel.
Flint found itself on the popularity list for a few years in 1959-60, but would prove a distinctive choice today.
Flint has superhero overtones--there's one in "Spiderman"--aka Sandman--and Captain Flint was a Marvel comic, and Flint is both a legendary pirate and a parrot in Robert Louis Stevenson's Treasure Island. But on the softer side, there's also inventor Flint Lockwood in Cloudy With a Chance of Meatballs.