You see this option on a lot of the high-end cars...Cadillac and Lincoln. May not get a lot of bids! The seats are listed in the "Air Intake & Fuel Delivery" section.
I've seen the seat back locks on Rivieras. It's easy to spot a car with them because there's an additional door jamb switch for the seat back release. The thing I don't like about them is that they draw power as long as the door is open.