Hey,
This patch provided motion blur using elbeem bluids in cycles. The implementaiton is similiar to the Blender Internal render (using the speed vectors of the simulation as indication where and how much to blur).
I have had this patch laying around for quite some time and never had time to commit this.
Maybe someone likes to catch this up and bring the patch up to par with blender git head!
(I'm still upgrading + installing my system)