Ah, the sweet smell of desperation. Unlike the smell of success, it tends to accompany fallen pop stars, singers who’ve failed to “make it” in the showbiz, and more than a few ladies with a laundry list of divorces and annulments under their garter belts. Currently reeking of it are Madonna and Britney Spears who, as we noted yesterday, are planning a musical (well, under their definition of “musical”) collaboration that promises to top any and all racy stunts either has pulled in their respective never-a-dull-moment careers. And now Us reports that, beyond bondage scenes and nudity nobody wants to see anymore, Britney has filmed a video clip for the performance that sounds like Attack Of The Killer Umbrella-Bearing Baldie 2: This Time, With Hair! Yes, we’ll soon see an enormous Spears at her “screaming,” “kicking,” “anxious” best, giving a whole new meaning to elevator music: