[EricH]

It's been a while since 330 did one of their blue lifts...but the last time one of those broke, it was self-inflicted and it merely bent.

Lifts do not have to have their extending sections inside each other. In fact, it's a lot easier to do a cable-powered lift if they are not inside each other.

I'll mention cabling routes here...

There are 2 types: continuous and cascading. See this thread for explanation. (post #3) If cabling is used, it is best to ensure that there is a "gravity" cable to make sure that your lift can retract.
There are, of course, other means of telescoping.

If a 2-tube-set lift has the sections outside of each other, each "level" has a partner joined to it in the other set. Joints are typically at the bottom and on one side.

You might want to take a look at 25's section in the 2007 Behind the Design book, as well. There is another robot in there as well--19??--that had a telescoping arm, IIRC, but it was an internal-section one. Oh, and don't forget to look at 357 in the same book...