Rob, I would be potentially be interested in one for a '70 Cuda with road lamps too. Keep us up to date if you come up with a solution.
I think John and I have figured out the 71 switching situation, a relay solution for 71 cars is done. I asked John to get some pictures of road lamp light plug inside your housings. I assume, I know dangerous, that 1970 use the same internal attaching plug. Once I know that plug, I can get a road lamp kit together using larger sized wire.
On a 1970, being a single headlight per side, I believe that you can run your road lamps with the car on high beam setting. Is that correct? There is no switching off of your road lamp when you go to high beams? I think that is a fed regulation about not having more than 4 forward light illuminated at any time. 71's have to switch off the road lamps, otherwise they have 6 lights.
If you have any pictures of your lamps taken apart and the internal connectors, I'd love to have them for reference. John's as well.
Please let me know the answers and any pictures and we can get a solution for 70 & 71 road lamp cars.
Performance for all the lights should increase dramatically.