Altering the view mode of rendered entities in a View Context via Ctools Plugin
I think you can bypass Views and get what you want with a content type plugin that does a query for the nids you are interested in, then passing that array to drupal_load_multiple(), then passing the result of that call to drupal_view_multiple().

drupal_view_multiple can take whatever view mode you want as a parameter, and will return a render array that you can just throw at whatever custom extra theming you need to do before displaying it.