It can be done for forums with no subforums in them, with a template edit.
ACP --> Styles & Templates --> Style Manager, choose your style and select
Edit Templates.
Find the template group,
FORUMHOME, double click on that, then double click on,
forumhome_forumbit_level2_post
In that template search for the following:
Code:
<ul class="forumactionlinks td">
Then after that add this:
Code:
<vb:if condition="$forum['allowposting']"><li class="forumactionlink newthreadlink"><a href="newthread.php?{vb:raw session.sessionurl}do=newthread&forumid={vb:raw forum.forumid}" title="{vb:rawphrase post_new_thread}" style="padding-{vb:stylevar left}:0;"><img src="{vb:stylevar imgdir_statusicon}/thread_new-16.png" height="12" width="12" /></a></li></vb:if>
This uses a one of the existing statusicons, but you'd obviously be free to change the image (in this particular location, 12x12 is the required dimensions).