Originally Posted by
PeopleAreIdiots
Im mainly concerned with whether or not sticking the cable through the stem would bend it too much, or if modifying the starnut is a bad idea.
You don't need a star nut. Use a compression plug to preload the headset bearings then remove it once the stem is installed.
You could then just glue the stem cap in place without the stem bolt.
If using a hydraulic brake you can bend the brake line as sharply as you want with no effect. A sharp bend in a mechanical brake with generate more friction.