There might be one in paper 2d. Since I do my work in FPS, I’m not sure that would help.
What makes the most sense to me is that they already have working elevator code in Unreal Tournament. Why not bring that code into the 4.11 build of the engine and make it a standard feature. Likewise, when one of their applications needs ladders (i.e. Spyjinx, Fortnite, Paragon, UT2015) just make it a new part of the engine. Of course, if there’s an indie partner that made ladders, maybe that could be included into the engine.