Alot of dressing rooms will go empty on the Great White Way this fall, as five out of the 13 shows set to open before Christmas only have one actor, a rate of 38%.Why so many? “Purely coincidence,” says Gerald Schoenfeld, chairman of the Shubert Organization, which is housing all five. “Some years ago, there were plays about people with disabilities, so I got some calls, ‘Are writers now going to be writing about disabilities?’ I said no. “Nobody is thinking that it’s the wave of the future,” he adds. Scott Sanders, a producer on the upcoming “Dame Edna: Back With a Vengeance,” has various theories. “There aren’t as many plays this year as there have been,” he says, linking the trend to the overall rise in celebs on Gotham stages. “Broadway has become a sexier stop-off in an artist’s career.” One entertainment lawyer offers another explanation: “It’s stop-gap producing.” Translation: When tuners and plays aren’t ready to go, solo acts fill the theaters. “The same thing happened after 9/11,” says the lawyer, pointing to the 2001-02 shows starring Elaine Stritch, Barbara Cook, John Leguizamo, Patrick Stewart, Simon Callow and Bea Arthur. Solo shows with marquee names are usually better commercial bets than multicharacter plays. Not only are the running costs lower, Sanders says, but an established artist with a core fan base provides a bigger insurance policy for minimum ticket sales, as opposed to bringing in a new piece of work that needs to be discovered. For example, “there’s virtually no risk in producing the Billy Crystal show,” he adds. He’s referring to “700 Sundays,” Crystal’s personal memoir that’s going up at the 1,200-seat Broadhurst, which usually houses musicals. Crystal’s Comic Relief partner Whoopi Goldberg is reviving her 1984 hit “Whoopi” at the 712-seat Lyceum. In addition to “Dame Edna”; there are “Laugh Whore,” Mario Cantone’s two acts of standup comedy and songs; and “The Good Body,” in which Eve Ensler of “Vagina Monologues” fame shifts her focus to the rest of the human anatomy, especially her own belly. Are the shows competing with each other? Will Broadway regulars get sick of all the quips, musings and anecdotes? Producers say they aren’t worried. “It’s really about first and foremost appealing to their core fan base,” Sanders says. Auds will expand if nonfans start to hear that a show’s really special. At this point, touring prospects for the one-handers are uncertain. “Dame Edna” and “700 Sundays” have no definite plans, while a spokesman for “The Good Body” simply says that a tour is perfectly natural given Ensler’s success with “Vagina Monologues.” “Whoopi” producer Hal Luftig says he hasn’t discussed a tour with Goldberg yet, but thinks she would be amenable, as would celebs in general. “I can’t imagine that a star would just say no for no reason. Ninety-five percent of the reasons I’ve gotten have to do with children. They don’t want to leave their children or uproot their children.” Tovah Feldshuh, for example, said she won’t go on tour with “Golda’s Balcony” in 2005-06 because her daughter is still in high school (though she will bring the show to Los Angeles in February). Cantone is not as well known nationwide as Broadway’s other solo acts. But Jonathan Burkhart, a co-producer of “Laugh Whore,” says he plans on a tour, the extent of which will depend on the show’s reception on Broadway. Cantone has notched prominent guest spots on “Sex and the City,” and Burkhart thinks the comic’s combination of manic flamboyance and down-to-earth Italian-Bostonian roots will help him appeal to a broad audience. “In any city, people know who he is,” Burkhart says. “You’ve got guys driving trucks, you’ve got elegant guys on Madison Avenue.” Burkhart hopes the show, the tour and a television special aired by his co-producer, Showtime, in the first half of 2005, will promote each other and up Cantone’s status. “Twenty years ago, when Whoopi Goldberg was at the Lyceum Theater, she wasn’t a household name, she was still working her way up the ladder,” he recalls. “Where Mario Cantone is today, he’s much further down the line.” One problem with touring solo shows is that many venues hosting Broadway series aren’t very intimate. “It would be difficult to go into a 2,000- or 3,000-seat theater,” says Luftig. Burkhart agrees, “I think we’d be looking at 1,000 and under” for “Laugh Whore.” If these shows fail, there are more on the way: Jackie Mason, Martin Short and Tracey Ullman are readying one-handers for 2005.