Views recipe: a list of user blogs, sorted by recent activity?

I'm using D6/Views2. I have a bunch of users, each writing their own blog (built-in core style). I'd like to use a view to generate a list of all of the users who have ever posted anything in their blog. I want to display them in a table, and while the default sort will be "most recently posted", I want to all the user to sort by name instead.

Do you know how I can filter on "has ever made a blog entry", and then sort by "most recent entry"? I started with a node view but then I end up with a list of (let's say) 12 posts by Bob, then 1 by Anna, etc. If Bob was most recently-prolific then he should be at the top of the list, but only once.

Thanks for any help!