Your problem with displaying the front license plate in the front windshield is the CA vehicle code severely limits what can be placed on the windshield. If you beat 5201 VC, you will get hammered for obstructing the driver's vision.
Pilgrim
5200. (a) When two license plates are issued by the department for
use upon a vehicle, they shall be attached to the vehicle for which
they were issued, one in the front and the other in the rear.
26708. (a) (1) No person shall drive any motor vehicle with any
object or material placed, displayed, installed, affixed, or applied
upon the windshield or side or rear windows.
(2) No person shall drive any motor vehicle with any object or
material placed, displayed, installed, affixed, or applied in or upon
the vehicle which obstructs or reduces the driver's clear view
through the windshield or side windows.
(3) This subdivision applies to a person driving a motor vehicle
with the driver's clear vision through the windshield, or side or
rear windows, obstructed by snow or ice.
(b) This section does not apply to any of the following:
(1) Rearview mirrors.
(2) Adjustable nontransparent sunvisors which are mounted forward
of the side windows and are not attached to the glass.
(3) Signs, stickers, or other materials which are displayed in a
7-inch square in the lower corner of the windshield farthest removed
from the driver, signs, stickers, or other materials which are
displayed in a 7-inch square in the lower corner of the rear window
farthest removed from the driver, or signs, stickers, or other
materials which are displayed in a 5-inch square in the lower corner
of the windshield nearest the driver.