Saab was actually the first company to have them.

I know Cadillac also has them as an option in certain cars. Some cousins of mine rented a DeVille when I was home for my sister's bat mitzvah, and I got a chance to sit on the vented seats.

Lemme tell ya, that's a freakin great feature. Makes air conditioning so much more effective because it cools you down right away rather than waiting for all the surfaces around you to cool down from contact with cool air coming out of the vents.