Creating thousands of blogs and users

Hello there!

I'm looking at creating thousands of sites each with a user. Now i see we can batch create, but what would be the best way for me to do this without having to manually create the users and blogs. I would also like to set them up with the same theme and generic content. The users will then go in and replace with their own content.

Is this the right plugin? Is there a combination of plugins I should use? Any tips would be of great help.

Best regards,