I love when people start talking about a 'unicorn' car. Does that mean it's unique? That there's only one left? That there are a few maybe still around, but likely forgotten about or left outside to rot. People are enthralled for barn find cars for this reason—any one of us who can see the numbers behind our stories sees huge demand. Why do you think all of these variations on the barn find theme have suddenly started popping up on TV?
(Also, why do you still have TV?)
Anyway, the SIVA Sirio was shown before the (Ferrari) Dino 206 GT in 1968 and was basically the same car, albeit designed by Michelotti instead of Fioravanti and with a Ford six-cylinder engine courtesy of the Taunus 20M sedan.
At most, you were looking at about 130 horsepower, up from the Taunus' 90 or so. Better, the Sirio's weight is said to have been a reasonable 850 kg (1873 lbs), and examples with the factory upgrades are believed to be capable of 200 km/h (125 mph). Not bad for an affordable sports car.
But what the heck is a SIVA? Well, Società Italiana Automobili Vendita was founded by the son of a wealthy industrialist who wanted to make an affordable sports car. There's a mess of information out there about ties with Bizzarrini and other players in the Italian sports car world, but the important thing to remember is that the recipe is the same: an idealist, a ragtag group of employees, and investors who want a return.
With the car first shown at the Turin Motor Show in 1967, production was announced at 300. How many were made between that time and when the company is said to have went under in 1969? Just three.
It's not the prettiest unicorn, but it'll do.