I went a little high end with
http://www.pioneer.com.au/au/product...0DAB/page.html
I do listen to J-Pop and J-Rock from time to time and am pretty sure that it handled Japanese. Not the same as Mandarin, but I imagine it would work.
In the end you will need to browse the manufacturors website (for your desired head unit) and confirm for yourself prior to purchase. One of those Android driven units might do the trick if you want to keep costs down.