The initial hints provided by the site, “V 20” and “F 30,” have now expanded into “V 20th Anniversary x F 30th Anniversary”. The “F” is probably referring to the 30th anniversary of the Famicom, which Nintendo themselves have been celebrating.
The former could refer to the 20th anniversary of Shueisha’s V Jump magazine. V Jump began publishing in 1993, which makes this its 20th year. This would mean that the game being hinted at is probably another manga crossover of some sort.
So, where does the Famicom part come in? A quick Google search shows that Bandai once published a crossover role-playing game titled Famicom Jump: Hero Retsuden on the Famicom, back in 1989. The game featured a variety of notable characters associated with Jump magazine, such as Kenshiro (Fist of the North Star), Joseph Joestar (JoJo’s Bizarre Adventure), Ryo Saeba (City Hunter) and more.
It’s possible that the new game is some sort of throwback or homage to Famicom Jump: Hero Retsuden. Either way, we probably won’t have to wait too long—Namco Bandai’s teaser site is scheduled to open in three days.