I bought a Pyle plr22mpf from Amazon a couple years ago, but it looks like it is no longer available.
You can get the Pyle plr14mpf from Amazon for $22.80
One option is looking on e-bay.
A couple more expensive options are RetroSoound USA http://www.retrosoundusa.com/products/category/id/1
or custom autosound http://www.casmfg.com/radios.htm
but those are pretty pricey.