It can pretty much be done right now in the scripting system, but it takes some mathematical skill and some clever coding. I'm doing such things in my game right now. You have to devise your own waypoint system though and cannot utilize the existing one. There was someone else on the forums that provided some movement scripts to do this as well. I can't remember his forum name at the moment, but there were even some videos showing this off. I did my own a little bit differently, but same kind of results.
System Specs: OS - Windows 7 Home Premium 64-bit SP1, CPU - AMD Phenom II X4 945, 3.0Ghz, RAM - 8Gb DDR3, GFX Card - 2048MB NVIDIA GeForce GT 640, FPSC-R Version - Beta 1.0071