Is there a way to create a new custom tab in the backend product edit page and then add certain attributes to that tab without using a .phtml file and without creating a custom group and assigning the attributes to the custom group?
It worked to extend the custom tab from Mage_Adminhtml_Block_Widget_Form and then create a new Varien_Data_Form, add a fieldset and add new fields. The field names must have the following format product[attriutecode]. The attribute can be loaded using Mage::getSingleton('eav/config')->getAttribute(attributecode).
If the attribute has options, $this->getSource()->getAllOptions() to get the array for the options value when adding the field.