Dave,
If you want good clean oats you have to pay for them, if you are willing to settle for ones that have been through the horse once you can get them cheaper. Having said that, I would recommend UVIRA, (541) 474-5050. They are definitely not the low cost choice but their process is different. Their process is used in space satellites and medical mirrors. You have to have your reflectors nickel plated before you send them to them. They apply an aluminum coating that is then sealed. It is almost as good as silver to start but will last a lot longer. Be sure to start with good original (not repro) reflectors. Repro reflectors have the reputation of being the wrong shape. You should also post your location to get a local source if you decide to go silver. Also a local shop that chromes bumpers should be able to recommend some that does nickel (don't use chrome).
Charlie Stephens