Private Themes
Wanting to take an MU theme and only use it for your page on the site?
Yes, you can hide themes from users and its really not hard at all!
First step is to upload the theme which you wish to use, do NOT activate it, this will keep it hidden from others. Now click on Blogs in the Site Admin. Here you can mouseover the blog you wish this theme available to and select Edit.
Almost done, in the top right you should be able to activate the theme on that blog and click Update Options just below the list.
Now that particular blog has that theme activated for it!