Such a movement already exists - the "Restoration" movement, which includes the Cambellite "Churches of Christ", the "Disciples of Christ", and other "no creed but Christ, no law but love" denominations. Odd that this "Emergent" movement hasn't hooked up with the "Restoration" churches, either.
Assuming that "returning to more 1st century ways" is the Emergents' primary intent (and assumming the Restoration movement is doing it right), I think Leonard210's summation is most accurate:
From post #19: "This is simply the "youth" culture isolating themselves from their elders"
Be careful who you place in this category. By the standard of many in "churches" Christ Himself would have been labeled the same way.