Creating separate page.tpl.php:
Let come to the heart of the topic, by reading the above explanations you would have obtained a pinch of salt about the real scope in using page.tpl.php and hook_preprocess_HOOK.
Now do the following:
In active theme's template.php file add the below hook_preprocess_page() implementation,
page--node--page.tpl.php, etc. will be our per node tpl.php page.
Of course to be created by forking page.tpl.php, this will help you to have different page structure based on the content type.