Roofrack mounted lights would only be illegal if wired in to operate with high beam, by my reading of the regulations. If questioned, the owner would refer to them as work place illumination lights, specifically mounted away from the front of the vehicle so as to not be confused as driving lights.
On a recent trip through central QLD I came across some vehicles with incredible lights, blinding up close. I didn't have a problem with them, unless they were thoughtless and didn't dip until too close. The law states one must dip high beam when within 200m of oncoming vehicles, and this might also be a victim of technology, as 200m seems too close with some lights.
Personally, I dip my high beams as soon as possible when I see an oncoming vehicle.