Proof that rumours can come true (and also that the PS3 just lost another promising title), the latest issue of Famitsu states that Beautiful Katamari is no longer coming to the PS3. 360 yes, PS3, no. No reason was given for the cancellation, so your guess is as good as mine. Providing your guesses involve either moderate sums of MS cash or the tricky nature of the PS3's architecture, making ports difficult. If they don't, they're rubbish guesses, and you should really try harder next time.
Beautiful Katamari PS3 Cancelled [neo2046 @ NeoGAF]