First, I love K2. This make Joomla do the stuff Drupal does -- only better.

Second, I am editing tag.php to customize the layout to look like my category listings.

I need to include a download link for attachments.

When I do a <?php print_r($item); ?> I see that I can access nearly every field and property EXCEPT for the attachment.

Is there a setting I am missing? Or is it even possible to pull attachments into a tag list?

Hello,

The attachments are not available for the tag listings.
You can insert them manually by editing core files (/components/com_k2/models/item.php) but I strongly recommend against doing this.