Nostalgic Heroes, a small toy company located in Shizuoka, Japan, put out some cool Chogokins (or RetroGokins, as they call them) back in the late 90's. I bought my first two from the late-great Meltdown Comics in Hollywood and just received my third from one of the Mandarake toy stores in Japan through their website.

Nostalgic Heroes did what no Japanese toy line did back in the day: Put out a Chogokin (Diecast) version of not only Kikaida, but also his Side Machine and his nemesis, Hakaida. The closest anyone got was Popy's PA-03
Mini Side Machine from their Popinika line, which was about vehicles and ships, (plus it was tiny) so that doesn't count.

Both the figures and their boxes capture that retro feel, as if they would have rolled out in the 70's.

The boxes even come with the familiar foam padding and a flyer showing some of their other toys. And the best part: Made in Japan, unlike most of the modern Chogokins that are made in China.