Just discovered GeekTool (naff name, I know), a little OSX prefpane which will let me dump the output of a few handy things to my desktop.
Like tail -f or - and this is what I really wanted - composite some beautiful desktop backgrounds from Paul Bradley with the scary horrors of my munin or cactii graph outputs.
I forsee many graphs in my future.
Until now it was driving me absolutely nuts that OSX Dashboard will let you do this easily, but is fairly brain-dead when it comes to having a screenload of widgets that you can't really arrange nicely, or have functioning in the background. WTF, WTF.
Yay!