Car Podcast Downloader and Player

I'm tired of listening to the radio in the car...
The lousy music, the endless commercials... Instead, I like to listen to podcasts on the drive to work.

Nobody makes the car stereo that I want
I have not found a car stereo designed for handling podcasts.The closest thing that I have found is a car stereo that plays MP3 files from a USB thumb drive. It works, but it's not ideal for podcasts. If you have more than a few podcasts it is difficult to navigate through the list - and it doesn't keep track of podcasts that you have already listened to. Then there is the matter of manually deleting MP3 files from the thumb drive and adding new files when the new podcast is available.

The "A Hah" moment
Why not have the car stereo download podcasts when its sitting in my garage! The car is easily within WiFi range of my router. It should check for and download the latest podcasts at night. Then I wouldn't have to do all the running around.

Why don't car stereo manufacturers make something like this...
When I look at car stereos in stores or on the web they are obviously appealing to a younger audience with useless and even annoying blinking light shows on the display. I want a big display with useful information and simple buttons that allow operation one handed - without taking your eyes off the road. I don't want an overkill design with an Android like interface - simple is better.

My Design
My podcast downloader/player would not replace the car stereo, but would connect to the existing car stereo's audio input port. I'll leave the radio design and CD player hardware to the pros. This ad-on would be a relatively simple bit of hardware. The recently released Raspberry Pi would have more than enough CPU and memory. Just add on enough SD memory, and a WiFi adapter, some buttons and an appropriate backlit LCD screen, and of course the software to run it all. I'm definitely thinking C.

Configuration
The only configuration from the car would be the WiFi access point and password.
Selecting desired podcasts could be done from a web browser. Once selected, the rest is automatic.
The device wakes up briefly at night, downloads new podcasts. In the morning it's ready to go.

Final Note
This Instructable was entered into a design Idea contest, but was not developed further.