After trying so many of these methodologies I've come to realize that people just work differently. It's self-defeating to try to push Extreme Programming or whatever on someone who prefers and is efficient at working alone.
Maybe adopt some of Scrum/XP/whatever that can be adopted at a high-level, but trying to push it through a team composed of people with different personalities and different ways of working just defeats the entire purpose.
It's hard to shoehorn it into an existing team where some portion of the team doesn't believe the premise. For example, some people (introverts, Asperger's spectrum, etc) will just never be comfortable with pairing.
Pivotal doesn't have this problem because developers that don't believe wouldn't ever apply for a job there.
But, that doesn't help Pivotal in their consulting practice. Very few of their clients would have the same advantage.