Hey
I had a feeling that this might be a difficult task, but unfourtanely i dont see any way around it if we want to finish the game. I think we got the sonic way of doing it down (atleast to some extent) , but i believe it will have to be some sort of terrain finding system to work properly... Since the ground on which the player will be moving is animated with bones the angle of the terrain will change constantly.
We tried putting physics behavior on the detection box and having two boxes on each side of the detection box too keep it from spinning around completely when confronted with too steep slopes, but it didn't work out quite as planned. But your tank example seemd to pull it of nicely... looking forward too seeing updates on that!
Thx for your detailed reply!