I want to get something close to this as a post-processing effect. Any ideas?
I’m confused, you want the image on the right’s effect? if so, the “image effect-> blur” effect script should get you pretty darn close… 
If Squideey is referring to the bokeh then I don’t think it can be achieved with the existing blur effect script. It would be really nice though if it would become possible…
/Johan I
Someone made a shader for UDK : http://forums.epicgames.com/showthread.php?t=743037
It can be done.
I expect it to be far more expensive than the current dof and it needs a talented coder to work on a shader like this for unity.
Actually, Ole, who is responsible for all the cool new image effects in Unity 3, just showed me a bokeh image effect tonight that he is working on while improving the current DOF effect. Hopefully it will make it into the next release 
Ooooooh, awesome!