Unity , Torque 3D , Esenthel engine, C4 engine, LeadWerks, Axis Engine etc ... have complete tools for terrain creation from scratch (terrain editing , multi texture, grass, vegetation ...)

If you look for terrain games can it be RPG or action games and some complete solution and tools Shiva 3D i think is not the solution for you in this case if you don't have some extern terrain editor.