Theme request - Twitter - Facebook, or this one...

I don't know if this has been requested but is it possible, without ticking off anyone, to have a theme similar to a Facebook or Twitter which hides its features until you log in? In addition you log in via an email address and there are login and registration options on the front of the site. A registration process follows which gives the option of becoming a standard user or to purchase blogs. If not here I'm open to any other areas providing this type of theme that I can take and modify. Also willing to pay, if it comes to it.
If someone cared to share some plugins that would allow for this type of configuration I appreciate it greatly.

This site also has a look I'm seeking:
http://www.theclymb.com/great-value-on-outdoor-apparel/Marathon%20Image%20Ad/361?gclid=CLO0pLefvKwCFQyFQAod5VSrrA

Many thanks in advance