You can get the smaller bits as NOS items from the States for £50 to £100 each plus p&p and taxes, but the big money item is the ally tank.
The last one I saw for sale was:
http://www.ebay.co.uk/itm/cafe-racer...vip=true&rt=nc
It would be a shame to sell it as you probably won't find another, but if you do, don't sell cheap.....