If Dame Edna is to be believed, her image will soon appear on Australian postage stamps. As for her new show, Dame Edna: Back With a Vengeance!, the woman who inspires more gladiola waving than Morrissey, guarantees “at least one major laugh per half-minute and one falling off YOUR SEAT howling and crying every 3 minutes and 23 seconds. These statistics have been compiled by the Royal British Society of Theatrical Statistics.” Speaking of Moz, now that we think of it, he would make a perfect opening act for the great Dame. Ahmanson Theater, 135 N. Grand Ave., downtown; Tues.-Fri., 8 p.m.; Sat., 2 & 8 p.m.; Sun., 3 p.m.; March 28-April 9; $45-$80. (213) 480-3232.?