Tommy,
I love those. Back in high school, a very good friend of mine's dad had a black '69 Kingswood Estate Wagon, which was loaded with factory equipment including the hideaways. Several years ago, I was able to get my hands on a Modelhaus '67 Chevy Impala Wagon, which I converted into a Caprice Estate Wagon, painted like my friend's car.
I also built a '69 Chevy Impala SS 427, which is also black, with the Hideaways.