Anybody know where you can get one, or know if some generic cap from something will fit? Mine seems to have disappeared somehow. [roll]
You can get OEM parts from Ducati Omaha via teh interwebs. I'm sure a couple other places sell OEM stuff online as well.
http://www.ducatiomaha.com/products.asp (http://www.ducatiomaha.com/products.asp)
The cap for the overflow looks to be part # 893.1.007.1A ($3.99)
The radiator cap is # 893.4.006.1A ($16.99)