3D hexagonal tiles (CIV 5 style)

Hello everyone !

The title says it all. How would I create hexagonal tiles like in Civilization 5?
I already have the basic hex tiles logic down (including pathfinding and hex selection and info), the only thing left is the graphical part.
My think was, use Unity terrain, and then place each tile's respective prefab. This works well if the terrain is flat, but I want elevation.
How would I create random hexagonal elevation like in the screenshot above?
As far as I know, you can't add hexagonal brushes, but a round brush could probably get an identical effect so it's not the end of the world.
Now the real question is, how would I paint the terrain textures AND elevation during runtime (ie while the map is being generated) ?

 

Have you checked out Honey Hex on the asset store? @A'vee has made something that looks exactly like what you are after.

https://www.assetstore.unity3d.com/en/#!/content/21650