I got a brand new Nikon F100 from ebay with the glass inside the viewfinder broken. I sent it Nikon in Melville, NY and they did repair it. The replaced the broken part for a new one. It wasn't cheap (paid more of the repair than the camera), but considering I got a brand new camera back in perfect working order and with warranty... very happy with it.
It's good to know Nikon still does this service and has replacement parts available. (aa)