Cars and trucks are limited in the wattage that is allowed in headlights. Anything more than 55 watts is not allowed.
From what I have seen most of those 'special' and expensive bulbs are just a different color i.e. white or bluish and tend to bounce back fog or snow at the driver while blinding oncoming traffic.
You might try the old motorcycle trick with a pair of diodes. The idea is to wire the diode between the high and low beam wires. If installed right this allows low beam to function normally and when high beam is selected both filaments burn.
We used to pry the diodes out of a junk alternator but I'm sure you could get them from an electronic supply house or Radio Shack.