Just a quick note, here, but Gmaxwell's put some time into creating what we might call a "mapped tree" of en.wikipedia administrators, based on RfA nomination patterns -- here's a link. Pretty nifty. The data used to generate the table isn't perfect (difficult to parse), but Greg's invited people to have a look and correct any mistakes they can find.
Looking at some of the names and nominations, I see once more the importance of attracting and keeping the right people, for any project. I'm also reminded that I should put some more effort into nominating people (co-noms and failed noms weren't counted, both of which should have given me some links, if I remember correctly).