So I was surfing the web and came across a picture on Kotaku that caught my eye. At first I thought it was a good looking Metal Gear Rex model, then I did a double take when I saw Tau bits all over it. The article links to the Work In Progress forums and it shows how he kitbashed it some Tau Pirannas and a Hammerhead.
So anyway go check out his info. Oh and also the rules he came up with it.
http://z11.invisionfree.com/Work_In_Progress/index.php?showtopic=16926&st=0