Is there any way to display questions (and all the answers) that a particular user has answered. That is, select all the questions that a particular person has answered and display 10 (or whatever number) of questions and all the answers per page. Since I'm hoping for the world here, being able to specify a user and a tag would be even better.
Does searching for user:nnnn [tag] do what you want? e.g.
You could try to run a query on the StackExchange Data Explorer:
I'm not very familiar with the database scheme, but this could be a start:
select top 10 q.Id, q.Title, q.CreationDate, a.Id, ... from Posts a, Posts q where a.OwnerUserId = <USERID> and q.Id = a.ParentId order by q.CreationDate desc