I'm glad you mentioned this. BeamNG was actually founded out of a game called Rigs of Rods, which in turn was influenced by 1NSANE.

What you ask for is possible in Rigs of Rods (although soft-body on soft-body is usually enabled on a per-vehicle basis). There is a plane that ships with RoR (the Antonov) that actually starts to wobble and shake apart at high speeds (I believe above 150 knots).