Or just set it in the Dragon Ball universe. Have Whis tell Goku that the multiverse is much larger than they evercould have thought and all the universes are bleeding together and them and a group of warriors from across universes have to work together to defeat whoever is causing all this to happen.
The problem with setting stuff in Dragon Ball is that Yamcha could single-handedly wipe out the entire cast of... most series, really.
But I guess Whis could just magic them off to another dimension where the usual rules don't apply, or something.
The other 70s thing that was a Jump staple was the baseball manga. Captain Tsubasa was the first big not-baseball spokon in Jump, but before it we had Play Ball, Astro Kyudan, Samurai Giants, etc.
This made me think. Imagine the next Jump spokon is a baseball manga, of very good quality. If that happens, the reaction in Japan would be big (Japan two main sports are baseball and football). But how would the reception be in West, being a baseball manga? Thinking this knowing Ace of Diamond for example has fanbase. Or Touch or Major.
There is no 'the West' here. There's either Europe, where baseball is such a minor sport that most people have never seen a match, or North-America, where it's pretty much the biggest thing around.
So while the English market might show interest, French and German publishers/readers could be a lot more hesitant.
(Normally, having an unfamiliar sport as topic of a manga isn't a problem, because the story will explain what you need to know. But in most baseball manga, they don't make ANY attempt to explain even the most basic rules, so people who are unfamiliar with it are completely lost from the start and probably won't continue reading.)
I'm really wanting to see what will the next spokon be and what sport will it be. The only succesful spokon we have had lately would be Blue Lock (WSM). And Shuudan was really good, it still pains me the axe.
Blue Lock does an amazing job combining a spokon with a tournament battle manga. I wish more series would do something like that, it makes for a much more exciting story for people who aren't into sports in real life.
(I know most spokon are driven by the characters and that's fine, but let's face it, the plot isn't usually all that original or surprising.)