OK I've found a solution to the OP. It does remove the product model from page title, but I'm no php coder, so this solution may have side effects that I'm not aware of.
In includes/module/metatags.php, line 279, there is this piece of code:
Code:
$meta_products_name = $product_info_metatags->fields['products_name'] . ' [' . $product_info_metatags->fields['products_model'] . ']';
I deleted the later part of the code, so that it becomes:
Code:
$meta_products_name = $product_info_metatags->fields['products_name'] ;