A accounting question type with checkboxes on the left (debit) and right (credit) side could be created by just changing the display.html
If you have a given number of answers (10 or 12 or 14) and there is no shuffling of answers, display.html could be changed to create a two-row-table with first answer and check-box on the left side and the second answer and check-box on the right side looking something like the attached (faked) picture.
In display-html there would probably be a change in this section:
<table class="answer"> <?php $row = 1; foreach ($anss as $answer) { ?> <tr class="<?php echo 'r'.$row = $row ? 0 : 1; ?>"> <td class="c0 control"> <?php echo $answer->control; ?> </td> <td class="c1 text <?php echo $answer->class ?>"> <label for="<?php echo $answer->id ?>"> <?php echo $answer->text; ?> <?php echo $answer->feedbackimg; ?> </label>
</td> <td class="c0 feedback"> <?php echo $answer->feedback; ?> </td> </tr> <?php } ?> </table> In this case you can use the negative mark capability of the MC-Question type.