Regarding the 2 new MGS games.
The answer was revealed today in Famitsu. While we're certain Kojima is going to be kept mighty busy either way, he's actually only fully involved with Metal Gear Solid Peace Walker. The Metal Gear series father is serving as director, producer and game designer on the PSP title.
As for Metal Gear Solid Rising (confirmed in Famitsu to be for Xbox 360 and PS3), Kojima is serving as producer along side Kenichiro Imaizumi. He told the magazine, "I'm not the director. I'm not doing game design either. Although, I do issue complaints (laughs). But, not too much."
Looks like Kojima doesn't really want to make a 360 title :P.