At the risk of confusing those with http://creativebits.org/mac_os_x/semi...hidden_apps enabled (myself included), you could use a semitransparent duck. At the risk of alienating those with black, grey or white ducks, you could use a grey duck. At the risk of defenestrating those with the "Use Grayscale" option enabled in System Preferences > Universal Access, you could make the entire duck, including the beak, monochromatic. Both the grey duck and the monochromatic duck would need to use greys matching the brightness of the duck, i.e. a yellow duck would have a lighter grey than a green one would.

I love the connecting animation! I'm using the default signpost away, but otherwise, brilliant idea! I'm replacing Adium's innards with these.