I just tried blocking the button with a conditional and it didn't work. :| I don't think this is quite possible yet. I will continue to try and figure it out. I was using the following conditional
<vb:if condition="$forum[forumid] != X">
[NEW THREAD]
</vb:if>
and entering in the forumid where the X is in the forumdisplay template and it still didnt hide the button.
--------------- Added [DATE]1262386492[/DATE] at [TIME]1262386492[/TIME] ---------------
Apparently there is an issue with Forum Specific conditionals in the templates.
I just entered in the following code into forum display
<vb:if condition="$forum[forumid] == 148">
TEST TEST
</vb:if>
And the words TEST TEST were no where to be found in forum 148 :| May be a bug/issue. If we can figure out why the forum specific conditionals arent working, we can solve your issue