You can already select a skin per page if it is enabled in site settings. Skinning is not related to page content.
What the templates will allow is defining what features will be on the page and what panels they will be in and what their sort order is within the panel.
All the skins adapt automatically from 1 to 3 columns already based on which panels have content features in them, so you don't have to choose a special skin for a page just because you want to have features in different columns.
Best,
Joe