That's an interesting thought to just replace the whole line.
I think had we realized where the leak was from the beginning that might have been a good idea, but as of now, there's only a small bit of problem area left to be uncovered.
When we started digging on the weekend, where we thought the water line ran and where it actually ran were two different things. 
Yeah, been there, done that. In my case, we finally found the leak. It was a 2" pipe about 8 feet underground, I had to rent a small excavator to find it. I would think yours would be maybe a foot or so underground - still might be worth it for you to consider for the price, especially if you have septic field problems - I had to fix one of those too.
I do not like plumbing, any plumbing.