Most efficent way to create terrain for iphone?

I know you cannot use the terrain from Unity 3d so how or what is the best way to create terrain for Unity iphone? Im looking to create fairly good size outdoor levels.

any suggestions welcomed

thanks

a collection of distinct models so you can make use of unity iphones occlusion system. as all tris of a mesh are sent to rendering even those out of view, it would be a fairly horrible idea to push them in as one object.

if you have iphone advanced, static batching will additionally take care that multiple such objects, if they use the same material, will still run in 1 drawcall