Here are a few options:
http://www.lwidof.net/
http://www.evasion3d.com/xd_lw_intro.html
http://www.worley.com/polk/polk_confusion.html
Also worley's fprime does nice DOF as well.
There is also digital confusion which comes with LW.
As well as Wavefilter as a post blur filter
Most of these work best when used with LW's native DOF.
There are quite a few options really.
My favorite is XDOF2 from evasion3d.