The Trailer Hitch is about $318 US Dollars, I have also seen them on e-bay. It is the same one as the LR3 or Discovery 3. Check with a few dealers because my selling Land Rover Dealer adds about 20% to all the parts. I purchased my hitch at Dallas TX Land Rover. The wiring harness is about $108 and it takes about 1.5 hrs to install. It is ez.. I did it myself. For more info.... see http://rangerovers.net/forum/viewtopic.php?t=2386
Here in the UK, the ability to have the tow hitch is there, if you look under the rear of the car they all have the special hole where the quick release version plugs in, but the dealer reckoned that it should be specced at build as its cheaper to do than afterwards. I am a bit sceptical but ordered it anyway.