[Mr_I]

YES! We discovered that #35 chain fits almost perfectly between adjacent pieces of 8020. Add to that the fact that the steel-to-aluminum friction is very low, and you've got a very good thing.
We mounted two verticle pieces of 8020 to the drive train frame, and ran the chain down the slot to a "elevator car" that rides on two pieces of 8020 about 12" long. (There's about 1/16" gap between the car and the rails, so there's little side-to-side drag. ) The car is attached to the chain at the top and bottom, and the chain loops out the bottom via sprockets back to the top. Add a Barbie to drive the sprocket, and we've got a low friction high strength elevator!