The title says it all, there doesn't appear to be a new ebuild for xmlrpc to install it to the new location. I just upgraded following hte new guide (would have been nice if it would have mentioned that while hte new php is stable, all the PEAR packages aren't ;)). I've symlinked it on my server and it works fine, so presumably it's just updating the ebuild. All and all that was pretty painless.
This ebuild will be removed from portage soon... Please, use PEAR-XML_RPC or 'USE=xmlrpc emerge dev-lang/php'
To avoid confusion, PEAR-XML_RPC is now included in PEAR-PEAR ebuild compatible with dev-lang/php.