Toyota offers a CD/cassette radio on the Matrix. looks almost exactly the same as the base Vibe radio, except there's a cassette slot above the lower row of buttons and the one button is labelled CD/TAPE instead of CD/AUX.
http://forums.genvibe.com/zerothread?id=4306 I got one of these because it is just a swap out with the original radio, no wiring harness changes, plug 'n' play with the Moon & Tunes amp. There was one on ebay, and the seller had a high reserve which wasn't met, so I contacted him after the auction and we worked out a deal. I wouldn't buy one from a Toyota dealer, because their list price is insulting. If that hadn't worked out, I would have probably gone for a completely different unit, maybe one that also played MP3 CDROMs, and it would have still been a third the price of the Matirx radio from a Toyota dealer. So if you don't have a lead on a discount one from a Matrix, check out an electronics store that does car audio installs.I like books on tape also, get them from the library for free, really passes the time. Sometimes I get where I'm going and hang out in the car to find out what happens in the story.