Ajax Link In A FAPI tableselect Row
This can be solved by building a 'select' element with an option for each row id in the tableselect that gets an ajax link. Then we can add links to the tableselect row with '#markup' and use Drupal.behaviors to attach a function that sets the value of the select element and triggers its 'change' event. In the form building function, if $form_state['triggering_element']['#name'] is the new select element, $form_state['triggering_element']['#value'] is the one we want to process.

The select element could then be hidden and the in-row ajax links are still fairly clean. Of course this won't work if javascript is off.