yes a naked neck is a know breed, and you have to go by the standar if you want to show it, all though you can show any chicken if you want but you might not win or could get disqualified
the only recognized colors for naked necks are red,black,white and buff but like I said you can show any color
adding to above- a cross with another breed still would give too many feathers in necks. That's a sign of the bird not being pure for the naked neck gene. To get birds with 'right' amount of neck feathers, would have to breed naked neck rooster with naked neck hens to get chicks that have the right amount of neck feathers.
However, outcrossing is very possible to use in goal for a specific color and body type. Just won't be winning with the first generation birds due to bowties typically being too big in those.