Suggestion from Wes Felter and a good cup of coffee prompted me to write an implementation of Identicon using the canvas tag. If you are using a browser with canvas tag support (i.e. Firefox), take a look at the Identicon Canvas Test page. If not, the screenshot below will have to do because the example falls back to server-side identicon. I am going to hold off on deploying on my blog until I figure out how to get around a Safari canvas-related bug.
Feel free to use this at your own website.