Collapsible/hierarchical AND force-directed graph in d3.js

Question

There are numerous examples of force-directed graphs (i.e. nodes and links) and collapsible trees (i.e. parent-child nodes) but I cant find an example of the combination of thes

Answer 1

I'm also interested in this. I have found two examples, that I'd like to combine.

http://bl.ocks.org/mbostock/1062288 http://graus.nu/d3/