Depends what you want.
If you are an average sized person, getting a frame off CL will not be hard.
I just put together a vintage schwinn frame and the bike is right under 20lbs. So not super light, but I have inexpensive aero hubs (rear is a flip flop/so that adds weight too) that drive the weight up.
I put it together for a bit over $200. If you don't need a tall frame like I did I bet you could save some dough.
Number 2: Sounds heavy if weight is the issue 25.4 lbs http://www.mongoosebikes.com.au/bikes/detail.php?id=563
Number 3: Don't see the weight for 3, which probably means it is not a light weight. Most companies want you to know that their bike is light
So to me if light is the deal, some form of 1 is the best choice. You-build is probably the best choice. You will have more control and there not that many components to worry about. My advice is try to get as complete a frame set as possible. The old the bike the more complete it should be. I had hard time finding 21.1 mm quill stem.
Mr Crackmonkey's advice help me also