Thanks to @bikerumor for the write up on the BLKTEC X TOKEN Cable box system.

Token goes full Ninja w/ hidden cables, Shimano 105 shurikens & lighter parts.

Installed correctly, you won’t see anything on the outside, and you’ll still be able to turn the bar at least 90º in either direction. Look for BLKTEC stem and bar compatibility at first, with other brands likely to follow.

By Tyler Benedict -November 10, 2019 at Bikerumor

Definitely the top option if you want to go full ninja mode on your bike 🙂