WHAT does it take to tempt Barbra Streisand back on to a concert stage for, say, two New Year's shows in Las Vegas? How does US$20 million (HK$155 million) sound? According to the Wall Street Journal, the performance-shy star has tentatively agreed to do shows on December 31 and January 1 at the splashy, soon-to-be-opened MGM Grand, billed as the world's largest hotel-casino. The New Year's Day show at the casino's 15,000-seat arena would also be a pay-per-view TV event, which sources say could boost her take from the gig to the US$20 million mark. MGM Grand executives say no deal has been signed.