Motori 7 made a purpose-built 80cc mini-KZ for 11-14 age bracket, some 5/6 years ago. Platform would be ready to go
The concept has been toyed around for a long time so I assume all major brands have the potential to do that and/or had prototypes ready. Also if I recall correctly, back in the '80s there was a CIK 125 Junior Shifter category, but I don’t recall if it was just age bracket or if it had different carb/exhaust