How to override default page.tpl from a module, for a specific page?
As per Stuart Clark's advice

All you have to do is to create a template, for example : mymodule/theme/special-page.tpl.php

and add this to your module

function mymodule_theme(){
  return array(
    'special_page' =&gt;  array(
      'template' =&gt; 'theme/special-page',
      'render element' =&gt; 'page'
    ),
  );
}

function mymodule_preprocess_page(&amp;$variables, $hook) {
  if ( my_condition() ) {
    $variables['theme_hook_suggestions'][] = 'special_page';
  }
}