The perry plastic horses come with several varieties of armoured barding
Actually, the Perry horse sprues (which are available separately on their webstore) do not come with any barding, though one of the horse heads has a protective plate in the front.
The bardings to go with them are provided in the plastic sprues with the riders. The 1450-1500 mounted men-at-arms version comes with two Italian style and two German style plate bardings per sprue, while the 1415-1429 knights version comes with a mail barding and small chest piece per sprue.
That said, these horses might be in a bit more dynamic poses than the original poster might be looking, and the reins certainly would need to be removed and resculpted (easier to do with plastic than metal, though).