The "User Management Console" solution (in Marketplace) has an Import Users feature that accepts a very simple comma-separated (csv) format with three fields. CSVs can be created and manipulated in Excel. It's also included in the "Cloud Administration Tools" solution.
The "Sample Templates" solutions also allows to set up security for multiple users in Excel.
For something a bit more complex, there is the "Provision Request Manager" solution, that basically monitors an SQL database table that you define and manage.
In the worst case, you can always open the extracted XML in a real text editor (Notepad++ , jEdit...). The XML is indented, so it should be pretty easy to manipulate by copypasting rows.