Wilt the Stilt could become Wilt the Stamp if a grassroots effort to get the Hall of Famer and the only NBA player to score 100 points in a game on a commemorative U.S postage stamp is approved by postal officials.  Chamberlain's image on a stamp might be the only way the 7-foot-1 basketball icon could ever be cut down to size.  "I'd be very proud if that happens and I'm sure he would be, too, if he was alive," said Selina Gross, Chamberlain's sister. "I think he'd be very honored. He probably wouldn't believe this could happen to him."  The cause was started by sports writer Donald Hunt of The Philadelphia Tribune, a 123-year-old newspaper that primarily targets the black community. Hunt, who recalled as a child watching in person Chamberlain play for the 76ers against Oscar Robertson and the Cincinnati Royals, believes "The Big Dipper" has the credentials to join Jackie Robinson, Babe Ruth, Joe Louis and Jesse Owens among the sports legends with their own stamps.  "People should remember the great ones," Hunt wrote for a Feb. 15 story. "They don't come any bigger or better than Wilt Chamberlain."  Chamberlain starred in the NBA from 1959 through 1973, when he played for the Philadelphia (later the San Francisco) Warriors, 76ers and Lakers.  The 31,419 points Chamberlain scored during his career stood as a record until Kareem Abdul-Jabbar broke it in 1984. Chamberlain, who never fouled out in 1,205 regular-season and playoff games, also holds the rebounding record with 23,924.