Nodes would still work with actors of varying heights, right? I think I know what you're talking about; like in the Sly Cooper platformers, that would happen with buttons to push, or hooks to latch your cane onto. That would be nice; maybe with a system like that Bethesda could actually incorporate ladders into their level design.
For Skyrim, Bethesda used Havok Behaviors for their animation middleware. I think shortly after Skyrim came out (or late enough in its development that it wasn't viable), Havok put out a more comprehensive Havok Animation Studio SDK. Robust, but there isn't much documentation for modders to go off of when they want to incorporate more than just a scripted idle animation.