The default theme is as you see it on the
Vantage demo site, with the main map at the top of the page being an optional widget. The site you mention has been customized, so yes it is possible to achieve this kind of layout also through customization, but it's not a default layout option available in the settings of the theme. There is no setting from the front end for other users to post blog entries, so they'd require access to the
wp-admin dashboard at some level in order to make posts.
AppThemes does not offer customization services, however we do have a
certified partners page where you can find developers for hire who are experienced at working with our themes. If you make contact directly with an outline of your requirements, they can provide a quote for the work. Thanks.