Yeah I'm thinking they'll pin the 30th anniversary on TPHD. Won't be anything like 5 years ago.
Doesn't need to be either really, "25" is more special than "30", and these events also lose their impact if they celebrate every time. Just have a big blow-out when the series turns 50!
Voted "Zelda Maker" though. Would be a dream, but I realize it's probably unrealistic for something like it to ever happen.