I have a idea on how you Outerra guys can add tracks/treads into game, you may already know this way if you've used blender.
I will produce a video to demostrate what I mean in blender if needed, but basically you can use the blender bezier curve/circle function to define the area&direction of a track, then have Outerra function similar to how blender works and that is run a polygon (TRACK bits) along this curves path and as Outerra engine does this it defines that track bit in an array similar to how wheelparam works (allowing modder to access it and adjust parameters etc...).
The track would be initiated by script to define 1) track spacing 2) number of bits 3) other standard wheel params. By having a trackparam function you can then combined it with wheelparam to either setup suspension bits that move but don't interact with the ground, and also be able to define additional wheels for the purpose of creating HALF-TRACK vehicles.
Like I said I will show video of how it works in blender and is quite clever, you can use this in blenders game engine to create a functioning tank and track system and I think it would be perfect for Outerra. Each track bit is basically treated like a wheel but outerra can move/transform it along the bezier curve just like how you do it in blender.
PS. let me know what you think, perhaps I'm just rambling and don't know what I'm talking about? or the idea is old?