put another way, how can a user obtain an item partially from a server they operate, without being able to associate a piece of data on their server with the item they obtain? PIR via numeric index is clearly out as the data at the numbered index on the server will be associated with the file the client obtains. I think that single server is also out as well, if the user has total access to the only client and server involved I think this is pretty clearly impossible. I don't know if there is even a solution to this problem yet, or if it is even possible, but it would be a great way to get strong censorship resistance.