Hi Periboob

About the weight of the cable I read that being of nano tubes could be around 1500 tons only.
Anyway, what I don�t belive it would easy to do is the hole balance in every condition. I mean, this is supossed to carry heavy payloads, so you have to design a counterbalance to keep the balance with the payload going up (changing the center of gravity of the elevator), and also when nothing is going up...
There is a tech site ( here ) with many maths formulas about some problems about the elevator. It�s a litlle old, but interesting.

After reading many sites about the elevator I have the feeling that the methods of carrying material to space we have today are in their limits. We are like in "prision" now (in the Earth I mean). We can�t do more than sending a small robot to mars. No more than that. And I also see real interest in such proyect in NASA. This was hard to imagine in the 70�s, so I�m confident that something it�s going on. Isn�t about making a modern shuttle. No, there�s a revolutionary solution to come. I don�t know if would be the elevator as we know today, but something it�s in the "oven"...