The JVC KD-NXD505 replaced the JVC KD-NX5000 as installed by our very own SRT6nTulsa:
http://tinyurl.com/ca3baa
http://tinyurl.com/d38rhk
http://tinyurl.com/bpzb5z

I, too, cannot understand why the JVC website lists the KD-NX5000 but not the newer NXD505.
They do list the owners manual and install guide:
http://books.jvcservice.com/booklist.asp?Model=kdnxd505