Wouldn't the concept of using counterbalanced ascent and descent modules be the way to go? Or is that just too SciFi for the available technology?
I guess that would necessarily mean having a larger nanotube trunk with a smaller nanotube 'rope & pulley' system suspending the ascent/descent modules, with an equal weight of modules going up and down.
Maybe that's too complicated for current technology but considering that a space elavator will be enormously expensive, why not do it right the first time? If it's doable this concept seems ultimately to be technically simpiler that the climbing concept.
Designing the power, mechanical, safety & control systems for these bulk lifting containers sounds complicated and expensive as well. Climbing 62,000 miles lifting a payload out of the gravity well will take a lot energy. Same problems for descending with less energy.
Linear motor.. microwave or laser powered..