Not sure if it would viably work within windows itself, as every selection rectangle etc would be out by the width of your arrow cursor.
How an icon is drawn in a 32x32 square, the arrow cursors are typically drawn in their square with the left-hand straight side being flush against the left side of their square. I don't know the reasoning for this action, but it seems to be a typical going on.
Hope that makes sense what I've just said!