youd be suprised how much damage a hope hub will take and is still perfectly useable. the ratchet ring is made of cromoly steel (i think, its some hard steel anyway) and can be replaced but the wheel/hub would really need to go to a GOOD bike shop or back to hope to have the old one removed and the new one put in. the freehub body on a bulb was made of titanium, and do break, but are very unlikely to wear out. they show hairline cracks , and it is then that you may not need to replace it, but certainly keep an eye on it. they are still available from hope, a good bike shop would be able to order it.
as i said, i would be suprised if you need to replace the ratchet ring, they are very tough. just get the pawls and springs and enjoy.