Load ad-busters from the theme if the REQUEST_URI matches one of the whitelisted requests.

x_maybe_load_ad_busters.php

<?php

add_action( 'init', 'x_maybe_load_ad_busters' );

function x_maybe_load_ad_busters() {
	$ad_busters = array(
		'/adcentric/ifr_b.html',
		'/atlas/atlas_rm.htm',
		'/doubleclick/DARTIframe.html',
		'/eyereturn/eyereturn.html',
		'/flashtalking/ftlocal.html',
		'/pointroll/PointRollAds.htm', 
		'/unicast/unicastIFD.html',
	);

	$request = $_SERVER['REQUEST_URI']; 
	$request_path = parse_url( $request, PHP_URL_PATH );

	$index = array_search( $request_path, $ad_busters );

	if ( false === $index )
		return;

	$output = '';
	$file = locate_template( array( 'static/iframe-busters' . $ad_busters[ $index ] ) );

	if ( $file )
		$output = file_get_contents( $file );

	echo $output;
	exit;
}