There are some necklace spacer bars, with matching necklace ends, that do what you are talking about, but not on as grand a scale.
Ours are designed for only 2 to 5 strands, with each strand being only about 1/4" away from the next.
Catalog Page 31 Perhaps the designer of Selma Hayek's necklace made their own speciallized necklace ends (with the right number of loops, and the right distance of spacing). Without seeing the back, I wouldn't know if it was wire-wrapped, fabricated from sheet, cast ....
If the necklace reminded you of the stacked-ring neckwear from Africa, then the necklace end a the back was probably fairly tall and fit up along the back of the neck, with a clasp at the middle of it (or maybe one at the top *and* the bottom).
-Polly