I think http://stanlemon.net/pages/jgrowl is very close.

  jGrowl is a jQuery plugin that raises unobtrusive messages 
  within the browser, similar to the way that OS X's Growl
  Framework works.

It is pretty old by now (4 years), but a benefit of that is that it supports older browsers too.

And this plug-in is also close. Build on top of jQuery UI, so small footprint, but you'd need that library.

http://www.erichynds.com/examples/jquery-notify/

  This is a growl/ubuntu-like notification system built on 
  top of jQuery UI.