How is factory pinstriping applied? Is it a sticker or is it painted
on. Can it be removed? Specifically, I have a 2001 Ford Crown Victoria
that I would like the pinstriping removed from. Any idea on cost? Car
is white and pinstripe is grey.

Perhaps this forum will be helpful to you:

http://www.focaljet.com/ubbthreads/showflat.php?Cat=0&Number=1021342&an=0&page=6

you might be able to tell if the pinstripe is painted or a decal by
inspecting the inside of the door where the pinstripe wraps around out
of view.

A lot pin striping is self adhesive vinyl.  Some is screen printed
with patterns and some is inkjet printed with solvent inks.  Some pin
stripes are cut with vinyl cutters and some are punched out with dies.
 Commercially these are removed with hot air guns that are normally
used for paint removal.  Obviously you keep the hot air at a distance
from the vinyl pinstripe so that the hot air will not damage the paint
yet will gently heat the pin striping.  When it is softened it then
can be easily peeled off.  Remaining adhesive can be removed with
special adhesive remover available at sign supply companies. This will
not damage the original paint surface.  Sometimes after removal marks
in the paint will be left.  These form an outline around where the
original pin striping was applied.  This is caused by pressure washing
of the vehicle.  Small nanometre sized particles of grit remove some
of the paint along and around the edges of the vinyl.  Good luck

Thank you Chango and Jeremy for the comments. Inspired that it could
be done, I went to a body shop. It is painted on my car. They are
going to use a solvent to remove the top clearcoat and then a special
grinding disk to remove the stripe. When the're done they will buff
and reapply clearcoat. They said they do this all the time for people.