looking for pluggable bb/forum

Hi all, does anyone know of good php forum software that does not take the approach that customizable headers/footers are used (like with phorum), but one that is plugged in the middle of a page, say by calling a function that displays the forum in it's current status, or by including a file? I cannot use something like phorum, as the setup of my site is too complex (relies heavily on auto preprend and append) and a lot of navigation and boxes and ... are to be placed around the actual forum functionality. Any help is appreciated. Thanks, Ben