1.) almost everyone's home page here will show different styles of vBulletin.
www.pixeladdiction.com uses vb as a core for user authentication in several non-vb areas.
2.) No, you're free to change the appearance, including the logo, all you want.
3.) I'm sure there are but it's a matter of finding them. YYou are only limited by your own html/css coding skills (or those of the person you hire) with respect to how you want the appearance to be.