pb4ugo is absolutely correct that some Cadillac Eldorado calipers had a cable actuated E-brake system. I think the applicable years are 1976 -1985. Those calipers used to be hard to find, and expensive if you could find them, but pricing and availability have improved.
My understanding is that if those Eldo E-brakes are adjusted perfectly, they will provide marginal E-brake performance. I also understand the adjustment process is a PITA, and requires frequent adjustment.
The FJ40 E-brake handle uses a single cable to actuate the transfer case mounted brake drum. The Eldo calipers require a cable to each caliper. I am not aware of any aftermarket supplier of a cable kit specifically for FJ40 applications.
When my FJ40 went to “Original Proffitts” they installed a full floating rear axle assembly along with rear Eldo calipers at my request. Unfortunately, they did not connect the Eldo calipers to the FJ40 E-brake system. My plan was to use a cable setup similar to what Ford used on 1970s pickup trucks with a one-into-two setup with an equalizer bar. However, after doing some research, and learning the Eldo calipers are solidly mediocre, I decided to go a different route and purchased the transfer case mounted E-brake system for a split transfer case from Georg. I then bought Monte Carlo calipers from Rock Auto.
This was a very effective way of flushing several hundred dollar bills down the toilet.