According to the author of http://www.d3lexicon.com/, a complete list of all conversations is given here. The data is gathered from the internals of the Diablo III client.
You can filter the conversations by "Fol" for "Follower" at the beginning, then by "En" for "Enchantress", "Sc" for "Scoundrel", "Tp" for "Templar", and "All" for all of them.
Example "Fol Sc En Wrld 2" (talk between scoundrel and enchantress):
Scoundrel: However did you become so good at charming others?
Enchantress: I learned the charm spell long ago and spent many hours practicing it.
Scoundrel: That's not what I—never mind.
Example "Fol All Camp 02" (talk between all three followers):
Scoundrel: Kormac, anyone can tell that you are lonely. Let me help you find a woman.
Templar: I already told you: I have forsaken the pleasures of the flesh! How hard can that be for you to understand?
Scoundrel: There's no sin in merely talking to a lady, is there?
Enchantress: The way you talk, there is.
Example "Fol Player En Wrld 004" (talk between enchantress and player):
Enchantress: The templar is so strange around me at times.
Player: He's in love with you.
Player: You never noticed?