Как вариант... "Без родителей"...
<!DOCTYPE html>
<html>
<head>
<script src='http://code.jquery.com/jquery-latest.js'></script>
<!--
<link rel='stylesheet type=text/css href=tmp.css' />
-->
<style type='text/css'>
</style>
<script type='text/javascript'>
$(function (){
$('.search_item').click(function (){
var val=$(this).data('value');
$(this.parentNode).prevAll('.search_show_list').eq(0).val(val);
});
});
</script>
</head>
<body>
<input class="search_show_list" type="text" tabindex="1" autocomplete="off">
<p>test 1</p>
<ul class="list_modules">
<li class="search_item" data-value="1">Вася</li>
<li class="search_item" data-value="2">Петя</li>
</ul>
<input class="search_show_list" type="text" tabindex="2" autocomplete="off">
<p>test 2</p>
<ul class="list_modules">
<li class="search_item" data-value="1">Вася</li>
<li class="search_item" data-value="2">Петя</li>
</ul>
</body>
</html>