there are people that part out SVO's on Ebay and I have seen hoods there very reasonable, but the shipping would be expensive. your best bet is to get in good with a local pickapart and have them call you the minute they get in a 84,85 or 86 SVO. There is no real source for the hoods, you just have to get out the word and one will pop up.
they do make a SVO style fiberglass hood for regular Mustangs, you can find ads for them in Mustang Magazines.
Check the group below, the members might have one.