This might actually be something, especially if space stations on more planets become possible somewhen. You build a base station on the ground, pointing upwards, and another one on the station, pointing downwards. The cable could be rendered in a similar way to the Beacon's beam, though it should go farther up than just to y=255, if that's possible. Maybe there is a way to make the client render it depending on the height of the player who is looking at it?
Space stations seem to have landing zones, so I would say, the base has to be somewhere close to it. When activating the station's anchor point, it could just pick the closest in the landing zone. Or, landingZonePos+spaceStationAnchorPos-spaceStationBlueBlockPos, aka right under the anchor point. This way you could have multiple lifts for the same station.
I would suggest that you build the lift by first building the two anchoring points, crafting several spools of carbon nanotubes, and putting them into the upper one.
In the simplest case you would use the lift by just rightclicking either of it's anchor points and being teleported to the other end. For a little more sophisticated system, it could have a climber, which works similar to a rocket. You enter it, press space, it moves along the cable (aka, in a straight line up or down), makes the dimension transition, continues moving, arrives at the other end, and you can dismount. To make things easier, applying redstone to either anchoring point could make the climber move if it's docked (no matter at which point), and/or the anchors could accept launch controllers in order to make the climber move automatically.
Well, if this would be made with end-game materials, then I'd love to have this in the game also, if you could have space stations above the moon, mars and maybe other planets and have space elevators, then I'd love this to be in the game!
Maybe something simple like a anti gravity magnetic system that would need a large amount of power that would need roughly a 100 block structure on the planet that coudl shoot a pod up to a planet or so on but to balance it you would have to wait for the planet/moon/space-station to be calculated to be directly above you. The speed could be measured with high powered engine and low power engine to stabilize speed and direction. The little issue could also be solved by a more extravagant pod which has stronger speed and direction control