it’s not as neat as a joystick but I’m more than happy with the performance of my Solarforce L2 torch with an XPG drop in. You can pick then up for £24 ish from here:
http://www.kmnw.co.uk/store/index.php?main_page=product_info&cPath=22_73_88&products_id=317
or get them on Ebay from Hong Kong for a bit less.
You still have to buy the batteries and charger – @£25 (unless you are prepared to wait for Deal Extreme etc) and a Joystick mount (which fits perfectly)
It works out at @£70 – but there are cheaper (though IMHO) not as good torches on the deal extreme site for @ £10 if you want to go a bit cheaper