As revealed over the weekend, Konami roped in Bayonetta developers Platinum Games to make Metal Gear Rising, because it couldn't.
Originally, Kojima considered bringing in a Western developer after first planning on cancelling the game in late 2010. But, since this is a ninja game, he ultimately decided a Japanese developer would be the best fit.
The above documentary explains how the whole thing went down. It's twenty-five minutes long. Hey, this is Hideo Kojima! That guy is wordy.