Pimped-out Escalades, bubbling Cristal, and jigglin’ booties are so two years ago. The latest must-have hip-hop video prop is…a 6-year-old boy. Ever since Lil Max$o (born Maximillian Justn Flores) made his MTV debut striking gangsta poses in 50 Cent’s 2002 ”Wanksta,” his adorable mug and trademark tipped Kangol have appeared in clips by Nas, Angle Stone with Snoop Dogg, and Mase. So who’s his favorite rapper? ”50 Cent,” says the half-Puerto Rican, half-Mexican tyke. ”Cause he’s really good and nice.” A performer since age 2 1/2, when dad (and manager) J.R. Flores heard him reciting entire rap songs, the 40-pound Max$o rhymes, sings, dances, and even acts. Only thing this street Macaulay Culkin doesn’t do is take naps: He’s shot a movie (”Gas”) and will release a debut 14-song rap CD this fall. And while he’s not yet writing his own lyrics, his dad thinks he’s close — to which Max$o quips, ”Uh, I don’t know about that.” Pay heed, wankstas: That’s keepin’ it real.