I wonder if this solves the problem I've had of having a single APC cache across php-cgi children with fastcgi. From what I read handing the process management off to PHP would achieve that, is that what this is doing?
Oh cool, I have read that post before but must have skipped over it. I tried the hackish method in that last comment before but it gave me problems. At the moment given that it's fairly low load what I was doing I just left the default method in place which doesn't share APC.
http://pecl.php.net/bugs/bug.php?id=11988
How have you been managing the php-cgi children?