Tim,

I think most airlines that have "line-bidding" offer a number of lines that are made up of day trips or "out-and-backs". You are in your own bed every night. I don't like them very much because I would rather do 3-day trips and have quality layovers with the crew. I was just trying to illustrate the flexibility advantage that the "good" airlines have (keep in mind there are many "bad" airlines).
In many cases I have been awarded lines that subsequently became conflicted with my personal life, so I simply logged-in to our scheduling software and changed my whole schedule around in the matter or a few key strokes. Its amazing flexibility.