Thank you both for your quick and good answers! You are right, 90% of the functionality was already there, and I tweaked the include plugin to gein the rest. It may not be the best solution, but now I can add {{blinks>pagename}} and get the backlinks transcluded:
I added to "include.php" line 15:
$this->Lexer->addSpecialPattern("{{blinks>.+?}}", $mode, 'plugin_include_include');
and then to "helper.php" line 715:
case 'blinks':
$page = $this->_apply_macro($page, $parent_id);
@require_once(DOKU_INC.'inc/fulltext.php');
$pagearrays = ft_backlinks($page,true);
if(!empty($pagearrays)){
foreach ($pagearrays as $pagearray) {
$pages[] = $pagearray;
}
}else{
$pages[] = 'notes:dummy';
}
break;