I’ve posted this elsewhere, but thought I would give it a thread here if anyone is interested
create a plugin and check "OnWebPagePrerender"
then in properties assign your google code
I know it’s very crude, but to those who don’t care it might be good

it replaces </html> with the code+</html>
so if there is no html there, there will be no analytics code
I wanted to add the ability to prevent a loged in user (editor/manager) from generating hits, but couldn’t get it to work, so I gave up.
enjoy !
<?php
/* Handle event */
if ($modx->event->name === 'OnWebPagePrerender') {
$jscode = "<script type='text/javascript'>
var _gaq = _gaq || [];
_gaq.push(['_setAccount','".$scriptProperties['code']."']);
_gaq.push(['_trackPageview']);
(function() {
var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
})();
</script>
</html><!-- $isLoggedIn -->" ;
$output = &$modx->resource->_output;
$modx->resource->_output= str_replace("</html>",$jscode,$output);
}