In all my parts manuals and repair manuals for the Class III Boomers, there is no front mounted remote except the loader control. By that I mean that the front loader dual remote valve and joystick are plumbed with only the lift and curl circuits in mind. An additional front remote would require piping the rear remote quick connects to the front of the tractor or installing a diverter valve that would change one of the joystick functions to operate a grapple or some such front mounted implement. If New Holland has an OEM kit for the Boomers, I think it's only a recent addition because none of my manuals has any info on it.
I think it has been done, but just not with NH parts.