I'm doing something very specific to start with - just blood hits but todays build seems really useable. I definitely second tobbe's request about making the output frost compatible, it'd sort out motion blur and single particle culling issues really easily! I'm starting to get something quite useable now, this is rendered as an xmesh cache since I don't have lucid on our farm yet. Next up is trying an impact object into a blood sack (lots of arrows and swords in january) and playing with the pflow bits for streams of blood.
This build is playing far nicer with collision meshes - thanks!