A few years ago you could go to OfficeMax and pick up a (non-cordless) keyboard with a built-in trackball. Now you can buy a cordless keyboard without a trackball. Hmm..
I've never seen a cordless keyboard with any mouse-replacing devices integrated into it besides that little WebTV-looking keyboard from some company.. It was small and had a pointy-joistick-thing in the corner. Not something you would call "ergonomic".
So then, sorry.. Can't help you. Try google.com and type "cordless keyboard with trackball"..