Just stumbled over this
http://www.dissidentlogic.com/images/NormalOffsetShadows/GDC_Poster_NormalOffset.pngmain site:
http://www.dissidentlogic.com/#Normal Offset GDC Materials
Pretty awesome technique to get rid of shadow acne!
Needs a little extra work for a deferred environment though, as you can't really use the "high quality" normalmapped normals from the gbuffer
Works out of the box in forward shading though and is a nice improvement to A8's PSSM shadows.