php - Magento - Display product and category body page for each design in admin -

i need identify add cart button , disabled (js , php) based on product id(this not real aim of question, bold real one)
since haven't found solution have thought let admin press button in admin section dedicated tomy extension , capture button information js , save them later.
to display main body of product page , 1 of category each theme in design section.
how retrieve themes , packages:

//main package/theme mage::getstoreconfig('design/package/name') //reegex theme $ob=unserialize(mage::getstoreconfig('design/package/ua_regexp')); foreach($ob $key)     echo $key['value']; 

my main concern bold part, if possible? how do it?
clear: need red rectangle:
above there breadcrumbs , on right sidebar

more details
when admin creates/edit product, can select or not countries item can selled.
happens: when page load system check if item merchantable in costumers country otherwise removes button.
bring problems:

• wide theme support: i'm not sure button html same of default one

• in same page can exist merchantable , not-merchantable products: identify button of correct item in category page there multiple of them, check button behaviour: contains: /checkout/cart/ plus product id in onlick attribute or button submits form, think if admin "shows" me happens and, after analysis, able identify button , replace using id (secure) or class ( not certain), since not stores use default btn-cart class

• cache/fpc system fetch page: don't know if catch js disable button or if customer has disbaled script (probably can't use site), usualy add cart block not cached programs (sometimes if item not available button hidden)

• seo problem: guest aren't forced select country, try identify external service using ip, detect bots users, don't know if problem (i don't think so), otherwise have use js ajax call , hide button

i avoid edit template file , create simple way user set module( click button less complicated whole procedure create attribute, relatives options , associate sets)

basically: how can display product , category page in backend?

what using next logic removing button product page:

1. add new attribute (for example: hide_button, type yes/no) products in catalog > attributes > manage attributes. default 'no', products has button. admin can set attribute 'yes' needed products.

2. create observer catch catalog_product_load_after event:

   public function checkproduct(varien_event_observer $observer){     mage::register('hide_button', $observer->getevent()->getproduct()->getdata('hide_button'));      return $this; } 

3. create observer catch controller_action_layout_generate_blocks_after event , inject js code themes:

   public function injectscript(varien_event_observer $observer){     if (mage::registry('hide_button' == 1) {         $head = $observer->getevent()->getlayout()->getblock('head');         $head->additem('js', 'hide-button.js');     }      return $this; } 

4. create file js/hide-button.js remove buttons class 'btn-cart' page:

   event.observe(window, 'load', function() {     $$("button.btn-cart").remove(); }); 

i didn't test code, it's idea.