As car enthusiasts, we know all too well how many great cars were made, and, unfortunately, how many great cars were not made. Car companies love to tease us with exciting concepts, some of which have no change in hell of being made (Toyota Fun- Vii, I'm looking at you). However, some concepts could be made, and frankly, should have been built. Cadillac has a nasty habit of teasing us with great concept cars, and the Sixteen is one of them. It was exactly what Cadillac needed (and still needs, to an extent) to restart the brand, and there was nothing impossible about it. In fact, GM thought real hard about building it.
What other concepts should have been built?