Not quite what you asked, but...
We do list sites that require users to supply a user name and a password; for the site to be reviewed you need to include a trial username and password for editors to use with the submission, or an email address that an editor can easily get a free one without having to actually go through the sign up process itself.
Back to your question...
For a site that can only be viewed in some countries, and not others; well, you might hit a problem. There are ODP editors in many countries, and some people edit categories about countries other than where they live, or edit categories that have sites included from all over the world. If an editor in an excluded country reviewed your site, then it might get deleted depending on what exactly the page said, or it might be left to another editor to review. If the editor is able to review the site, then it will be reviewed.
What is so secret about the site that you only let certain people look at it?
<edit>beebware types faster</edit>