BTW, I changed the code in rcube_imap_generic.php to:
if (!strpos($user,'@yahoo')===FALSE) {
$this->putLine('a001 ID ("GUID" "1")');
$this->putLine('a002 LOGIN "'.$this->escape($user).'" "'.$this->escape($password).'"');
} else {
$this->putLine('a001 LOGIN "'.$this->escape($user).'" "'.$this->escape($password).'"');
}
This allows me to leave it in and use this install for both Yahoo! accounts and accounts on my domain. Sure there's a cleaner way to do it, but hey, it works!