It seems that those Mini-Z slot cars derived from 1:28 Kyosho Rc cars. Apparently there are 2 companies making chassis to be used with Kyosho bodies: Scholer
I have not found a complete kit, apparently you need to buy everything separate.
Where did you find those pictures? I noticed that Nick de Wachter was now producing a 1/28 scale chassis as well. I would love to run those cars as part of our club.
I was checkig what the brazilian clubs were running when I found those images. It seems that the 1/28 scale based on Mini-Z Rc cars is popular in Brazil, Portugal, France and Holland.