Perhaps you are looking for something like this:
http://www.ginnunga.org/forums/index.php?t=thread&frm_id=118
What I did was to add simple IF statements in the templates. In this case my code (you cant really use this, but it can give you a hint) looks like this:
Thread.tmpl -> thread_list and replace
{TEMPLATE-DATA: thread_list_table_data}
with
{IF: ($frm->id == 118)} <!-- IF NEWS -->
<tr><td style=""><img src="{THEME_IMAGE_ROOT}/news2.png" alt="News" align="left"><hr style="position: relative; left: -18px;top: 18px;border: 0px;border-bottom:1px dotted #aaaaaa;height: 1px;"><span style="font-size: 15pt; color: #660000;position: relative;top: -12px;"> Ginnunga news </span></td></tr>
{TEMPLATE-DATA: thread_list_news_data}
{ELSE}
{IF: ($frm->id == 124)} <!-- IF DOWNLOADS -->
<tr><td style=""><img src="{THEME_IMAGE_ROOT}/news2.png" alt="News" align="left"><hr style="position: relative; left: -18px;top: 18px;border: 0px;border-bottom:1px dotted #aaaaaa;height: 1px;"><span style="font-size: 15pt; color: #660000;position: relative;top: -12px;"> Ginnunga Downloads </span></td></tr>
{TEMPLATE-DATA: thread_list_downloads_data}
{ELSE} <!-- REGULAR FORUM -->
{TEMPLATE-DATA: thread_list_table_data}
{END}{END}
I also edited thread.php.t and after this line
$thread_list_table_data .= '{TEMPLATE: thread_row}';
added this:
$thread_list_news_data .= '{TEMPLATE: thread_news}';
$thread_list_downloads_data .= '{TEMPLATE: thread_downloads}';
Then I just went ahead and created subsections in thread.tmpl which were copies of thread_list and just renamed them to thread_downloads and thread_news and modified them to fit my needs.