Here’s a illustration of how to make some very nice looking group movement bases.
Modeling
Making A Wicker Fence
Barking Irons has a tutorial on making an english style wicker fence.
How To Make A Maori Pa
Here’s the beginnings of a tutorial series on making a Maori Pa.
Making A Medieval Hut
Here’s a set of instructions for making a rude hut for your dark ages and medieval games.
Making Cork Walls
Adventures in Lead has a post on making very effective wall sections from cork.