Currently ONLY (as of 2.5.3) saved searches can have RSS feeds.
 
This mod allows hardcoded searches like:
http://www.yoursite.com/index.php?m=search&issearch=1&gender1=2
to be RSSd, by adding &rss to the query string.
eg:
http://www.yoursite.com/index.php?m=search&issearch=1&gender1=2&rss
 
So in this example , with the above link, people will have access to an RSS feed for the last X females who joined your dating site, assuming:

gender1 value of 2 is a female
X being the number of results shown per search results page

It took me 10mins to write this mod, so please backup your code, and if you see any potential problems, or ways it could be done better, or bugs please let us know.
 
In my very limited testing with my site (which is not open yet) it seems to work, so fingers crossed.
 
Also this is tested with vld 2.5.3
 
In .htaccess:
Find
RewriteRule ^search/([0-9a-zA-Z]+)/?$ index.php?m=search&s=$1
 
Replace with:
RewriteRule ^search/([0-9a-zA-Z]+)/?$ index.php?m=search&s=$1&%{QUERY_STRING}
 
In lib.search.php:
Find the line starting with:
redirect(VIR_PATH . ($PREFS->conf['fancy_urls'] ? "search/$search_hash/
IMPORTANT: ONLY THE ONE WITHIN THE FUNCTION show_search($advanced)
 
Replace it with:
//MOD START
$rss_string = "";
$rss_fancy_string = "";
if ( isset($_GET['rss']) ) {
 
$rss_string = "&rss";
$rss_fancy_string = "?rss";
 
}
 
redirect(VIR_PATH . ($PREFS->conf['fancy_urls'] ? "search/$search_hash/$rss_fancy_string" : "index.php?m=search&s=$search_hash$rss_string"));
//MOD END
 
The final mods are all within the function show_search_results($hash, $page).
Find:
$TEMPLATE->set_template("search_results.tpl");
 
Replace it with:
//MOD START
if ( !isset($_GET['rss']) ) {
 
$TEMPLATE->set_template("search_results.tpl");
 
} else {
 
$search_orderby = 'joindate';
 
}
//MOD END
 
Find:
$search_orderby = $obj->query_orderby ? $obj->query_orderby : 'lastvisit';
 
Replace it with:
if ( !isset($_GET['rss']) ) $search_orderby = $obj->query_orderby ? $obj->query_orderby : 'lastvisit'; //MOD
 
Find:
$directionbox['asc'] = $LANG['search']['ascending'];
 
THEN PLACE AFTER (NOT REPLACE):
//MOD START
if ( isset($_GET['rss']) ) {
 
//------------------------------------------------
 
// Parse feed header
 
//------------------------------------------------
 
$output =
 
'<?xml version="1.0" encoding="utf-8"?>
 
<rss version="2.0">
 
<channel>
 
<title>'.htmlentities2utf8($PREFS->conf['app_title'] . ' | ' . $LANG['search']['app_search_rss']).'</title>
 
<link></link>
 
<description>'.htmlentities2utf8($PREFS->conf['app_description']).'</description>';
 
//------------------------------------------------
 
// Parse feed items
 
//------------------------------------------------
 
$TEMPLATE->assign('search_profiles', $profile_obj);
 
$output .= $TEMPLATE->result('search_rss.tpl');
 
$output .= '</channel></rss>';
 
header('Content-Type: application/rss+xml; charset=utf-8');
 
echo $output;
 
exit();
 

}
//MOD END
 
If anybody adds this their live site I would love to know, and see it in action with a more complete member base than my 10 test members.
 
A mod like this will hopefully keep your members coming back.