Change the cursor of the mouse

Hi,

I would like to change the image of the cursor of the mouse during an operation. For example the one use while the color picking.
Is it to change it with Python?

Thank you!

you can set the cursor with python:
http://www.blender.org/documentation/blender_python_api_2_69_1/bpy.types.Window.html#bpy.types.Window.cursor_set

but not replace the cursor as set by existing (C-written) operators with python.