Nope, you didn't accidentally click on a DVICE post from 1988: someone has actually launched a new cassette accessory in 2014, and for some of us, it solves a real problem. I drive a classic car, and like many people who appreciate the sense of character you get with an older vehicle, I don't want to stuff an ugly-looking modern car stereo into the dash. This adapter from Ion Audio fixes that issue by allowing you to interface your old car radio with the modern world.
The Bluetooth Cassette Adapter slips into your old car stereo's cassette player, and transfers the signal picked up by its Bluetooth receiver (from your phone or other audio source) straight into the cassette deck's playback head. A built in rechargeable battery powers everything Bluetooth receiver, with a USB port on the side for recharging. The adapter will work with any Bluetooth capable device, and it could also be useful if you use your phone for navigation, and want louder prompts than the puny phone speaker can deliver.
No word yet on when the adapter will be available or the price, but I'm going to try to find a way to buy one anyway.