My quick release hub along with two sprockets to match - original 38 and a lower 40 tooth - turned up today.
I got them from "scatman" who sells a load of stuff through ebay, but you can get it all cheaper if you go to his website:
http://www.ducati-shed.com/ I paid £118.50 in total for the hub and two sprockets - that's cheaper than some places charge for the hub alone!
They're really, really good quality too...