It's possible to create a new site directory:
1. Go to the Home page
2. Click on Modify Settings
[Change Settings under Actions]
3. Go to the tab where you can set what templates it offers when creating subareas. By default it restricts them on the Home page. Change it to allow any site template.
[Click on the Page link]
4. Go back to the Home page and create a new subarea.
5. Select Site topic area
6. Create it (if you deleted the old one you can create a new one with the same name and URL) and you'll have a new Site Directory where you can create sites.
=========================
In addition, there are some tips about how to modify sites page.
you can sneak into it by simply appending "&PageView=Shared" to the end of the URL once you click on the "Edit Page" link.
You'll notice, however, that the "Modify Shared Pages" link still doesn't appear - BUT, now, at least you can access the Web Parts - click the arrow for a web part and select Modify Web Part. This will let you modify the web part, and hide and move other web parts.