Several people have switched to halogens. As the new halogens don't seem to draw as much current as the first version models, they can be a direct swap.
IMO it would still be worth taking the current out of the old headlight and dimmer switches by adding relays. Not only would that reduce the strain on the switches it also would make the headlights brighter by using a larger wire directly from the battery supply to cover most of the distance needed to feed the lamps. You would use the several feet of smaller gauge wire in the original loom that it took to reach the switches and then return to the lights to work the relays instead.
Several have used relays and mounted them in various locations. When I did mine I made a module that would mount on the fender near the existing light junction terminal strip where connections could be easily made.
This is what I made for a 47. I used a similar approach on the 56 using 12v relays but another layout due to the different way the headlights are fed.