I purchased and installed an e-body replica radio from Antique Automobile Radio, Inc. It looks just like the original e-body radio but has newer technology internals. This one installed quickly and easily with no modifications necessary. It works and sounds great too.
Here's a link to the Antique Automobile Radio website where you can learn more if you'd like:
http://radiosforoldcars.com/newradio0F.htm
This radio was relatively expensive ($595). It was worth it to me, because I wanted to keep a stock appearance and still have a radio with modern sound and capabilities.
-------------------
Prior to finding out about the e-body replica radio, I had purchased a RetroSound Classic radio with Mopar knobs from RetroSound USA. It doesn't look like a stock e-body radio, but it has a retro appearance. I paid $300 for the radio. At the time, I worked with RetroSound directly to ensure that I would get a setup that would fit my 71 cuda. Since I encountered the Antique Automobile Radio replica, I never used or installed the RetroSound radio. It's still in the box.
Anyway, this radio may be an option for you. You can get more information from the RetroSound USA website:
http://www.retrosoundusa.com/
Or watch this video on YouTube:
http://www.youtube.com/watch?v=7TSWOhu0hTU&feature=player_embedded