Problem with a front head tube exit is
– clearance for rotating steerer, probably OK with 1 1/8th forks but would need an internal guide or sleeve to stop rubbing
– possible tight bend radius when the bars are turned or when you crash
In that case then I wonder how my Commencal Meta AM fits 2 gear cables, a brake cable and a reverb cable all through the tapered headtube, with tapered forks. 🙄
There is loads of room in there
The main issue you will have is the unsecured cable smacking the inside of your tubes and causing a really, reall,y really (no really) annoying rattling noise everywhere you go. Trust me, its annoying as hell!