Is it possibile to create a site with a sign on screen to ask for Username and password in a Skuid page so no one ever sees sales force. I understand I can redirect a user to a Visualforce page after sign on. Or is there anyway I can put “https://dorothy.my.salesforce.com/” inside an include page in a region
I looked for a solution like this in the past and only came up with using a third-party authentication service like OneLogin.com . I never actually tried it though.
What you are looking for is maybe the Salesforce community login https://help.salesforce.com/HTViewHelpDoc?id=networks_customize_login.htm&language=en_US
With that you are able to create login and registration pages where users can login. These sites are fully customizable (you can also put your own Visualforce-Pages instead).
But you probably also need other licensing.