I was thinking Miura forged TM 300 Forged, I once owned a set which had belonged to Gregory Havret. However they are 2002 clubs so just miss out on the OP's parameters.
As for Unicorn status I personally think that a Unicorn is something that we know exists but could equally be a myth as either nobody has seen one or next to nobody has. To that end the V steel cannot be one as my friend has one in his garage which he bought for next to nothing. His was cheap and is unloved.
My nomination for unicorn status are the JDM Taylormade R9 Forged irons.....stunning. I know they exist because I've seen photographs of them, just like I've seen photographs of unicorns and I once saw a set for sale on ebay, they were tatty and expensive. However I've never seen a set in the flesh, just like a unicorn.
I just sold my JDM R9's on eBay a few months ago...a beautiful club, beautifully forged and finished. I even played them a few times but was very careful.