How to add title of node (where order form was placed) to custom line item order in commerce
I found a pretty bad solution: I added to the node template the following jquery, which really just writes the node title of the current node to a field in the line item.

&lt;script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"&gt;&lt;/script&gt;
&lt;script&gt; 
    $(document).ready(function(){
        var title= $('#page-title').text();        
        $('#your-line-item-field-id').val(title );
        $('#your-line-item-field-id').prop('disabled', true);
});
&lt;/script&gt;