I'm curious how one should best understand the connections between the k-connected components when $G$ has minimum cuts of size $k>3$, or perhaps approximate minimum cuts produced by Karger's algorithm. SPQR trees answer this question for 2-connected graphs. And obviously 1-connected graphs are simply a tree of their 2-connected components.
For edge connectivity rather than vertex connectivity, there's always the Gomory–Hu tree.
Nagamochi and Ibaraki gave an algorithm to find a sparse $k$-node-connected subgraph of a given graph $G$ that contains $O(k n)$ edges where $n$ is the number of nodes in $G$. Not directly relevant perhaps but could be a useful preprocessing step. http://www.springerlink.com/content/u334lr0418n1719u/