This is a Geman TV documentary on master slot car builder Michael Niemas and even though it is not in English, you will want to watch this.
I doubt there is anyone else in the world building slot cars at this level. Feel free to correct me if I am wrong.
Here's a Google translation of the blurb at YouTube:
"For the trained model maker Michael Niemas, hobby, profession and passion are one and the same: he replicates racing cars in miniature format true to the original. The inventor is now building the 1/24 scale miniature cars for customers all over the world. Technically, the vehicles are small masterpieces and, like their big role models, can even be used in races. In this report, Niemas creates the model of a Lola T70 from the 1960s."
