I'm not sure they ever turned out to be more than vaporware. I know production samples were produced and sent to reviewers, but I never heard of someone buying one through normal channels.
Then again, maybe they did exist and it's just that no one ever bought one (and rightfully so, they were absolutely horrible, the reviews I read show that a lot of popular games at the time wouldn't even run). Factor in that it's performance was below Nvidia's Geforce FX series (and Nvidia was getting shredded by ATI at the time) and you had a very expensive mid range card with a high end price tag, and only if it would run games in the first place.
If they were sold though, someone's got to have one. You're right, I've never seen one in the wild. Not on ebay or anywhere. I did find a single GPU V8 that was refurbished, it weighs in at a hefty 100 bucks though (130 for 256mb version).
EDIT:
While we're at it, I wonder if anyone ever got a hold of one of the Sapphire dual GPU Radeon 9800 cards. They never left testing, and I'm not sure if they actually worked or not, but take a gander:
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