Let's see...
In W we had; Cyclone (Novel/Game only), Eternal, Joker and Skull.
In Kiva we had; Kiva and Dark Kiva using pretty much the same belt.
In Kabuto everyone had the same basic belt.
In Blade, Blade and Garren shared belt. Leangle shared his with the movie Riders.
In Ryuki everyone had the same belt.
You forgot about Kamen Rider Birth. Prototype and Regular versions.
In W, Cyclone/Joker and Joker were basically the same person anyway. Plus he got the "Joker Belt" at the end of it all. He just had a different belt that allowed him to transform on his own. Eternal and Skull are "Movie Riders" so they don't really count. :anime:
Kiva hmmmm, Dark Kiva puts his Kivat-bat in upside down, plus he has six Fueslots to hold the six Fuestles. While Kiva only holds three.
Kabuta no, because Kamen Rider The Bee had a brace, Kamen Rider Drake used a gun, and Kamen Rider Sasword had the Sasword Zecter.
Blade, Blade and Garren shared the same belt.
Ryuki, yeah I can agree with that. So that was the last time every rider wore the same belt.
10 years ago, so is this a little homage to that? What I was getting at, is that the "Primary and Secondary Riders" usually don't have the same type of "transformation" methods. Hasn't been like that in 10 years anyway. :anime: