pickwalks on polygon surfaces based on the view from the current camera (ie screen space)
Also has the option to add the resulting pickwalk to the current selection.

description and usage at top of the script.
version 2 update:
now works on verts, faces, edges, and combinations of any/all three.

version 2.1 update:
returns to the correct component selection mode

not in this update:
speed increase. it gets slower every time you use it :(
this seems to be due to the undo que. to "reset" the speed you can run the command flushUndo; however this will flush the undo que...
I will look into this for a future update.