The nice thing about this function is that you can place it just about anywhere with the thesis hooks. I have mine after the multimedia box, because I sometimes put both sidebars on the right and like having the search box above the other widgets.
/*Custom Search Box */
function search_up() {
<div class="sidebar">
<ul class="sidebar_list">
<li class="widget special_search"></li>
</ul>
</div>
add_action('thesis_hook_after_multimedia_box', 'search_up');
