Through steamvr/openvr you can add as many trackers as much as you would like to add. The knuckles controllers have been way overdue for 2 years and steam has left people in the dark on it's progress.
It would be cool if VRChat could add support for more tracking points for fingers for instance so third party hardware manufacturers can offer products right now to get more advanced finger or gesture control.
While piggy backing on existing drivers like five trackers is possible.. I'd like to see more... this would really incentive hardware development for VRchat. When hardware manufacturers have to ride on drivers of the big players they stand no chance to grow their product and improve a VR experience.