It would be very helpful to allow folks to optionally specify an XSL style sheet for the various output feeds.
Currently, I accomplish this by adding the following code:
// wp-rss2.php
//Line: 15
<?php echo '<?xml version="1.0" encoding="'.get_settings('blog_charset').'"?'.'>';
if (RSS_XSL_STYLE_SHEET) //-- jrc
echo '<?xml-stylesheet href="'.RSS_XSL_STYLE_SHEET.'" type="text/xsl" media="screen"?>'."\n";
?>
(obviously replicated where appropriate in the other feed files as well).
In my wp-config.php file I specify the define as:
define('RSS_XSL_STYLE_SHEET','http://blog.unitedheroes.net/isb.xsl');
Again, obviously, the usual portability wrappers could be used instead of the hardcoded path.