Well, I basically got what I wanted with a simple conditional in the posbit_legacy template:
PHP Code:
<if condition="($post['postid'] == $thread['firstpostid'])">
Then put in my modified, stripped down, article style template followed by an <else /> and then the standard postbit_legacy. So it works like the Vbulletin and CMS article above without any code modications. The only drawback is that the postbit_legacy template for the article forum is twice as long.