An Everlasting Piece is another of those small films that director Barry Levinson does between big-budget crud like Sphere. Since the small stuff includes Diner and Wag the Dog, that’s a good sign. Before whimsy eats away at the plot, this comic tale of Ireland in the 1980s is a treat. While Belfast copes with the Troubles, two barbers — the Catholic Colm (Barry McEvoy) and the Protestant George (Brian F. O’Byrne) — hatch a get-rich scheme. Both lads, who work at a Belfast mental hospital, learn that one of their nut-job customers, the Scalper (Billy Connolly), had been the only supplier of men’s wigs in Northern Ireland. With the help of Colm’s girlfriend, Bronagh (Anna Friel is funny and smashingly sexy), the barbers form a company, Everlasting Piece, to take over the field — that is, if they can best a rival outfit called Toupee or Not Toupee. The humor is slight, but the actors make the blarney go down easy. McEvoy wrote the clever script, based in part on his barber father, who once sold hairpieces. And Levinson keeps the laughs percolating without trivializing the Irish conflicts. Neat trick. Neat movie, too, though at nearly two hours it could use a trim.