Sorry, six Syaorans if we count the "twin" version of Horitsuba Gakuen. But those Syaorans are the same as TRC's Syaoran -sort of-... but wait! there's another Watanuki there, so it would be seven....? @_@
I feel like my brain is going to implode. >_<

So, yeah. Clamp must be having fun at my expense. :P