This Depth of Field mod has a head bobbing effect in it. You can just disable everything else except for that if you want.
http://www.newvegasnexus.com/downloads/file.php?id=35615
On a sidenote, if you'd like to have DoF along with your head bobbing, I'd actually recommend using the DoF in http://www.newvegasnexus.com/downloads/file.php?id=37216 instead of using the one provided in the mod above.