I haven't seen any of these on the site, so I wanted to challenge people to write a crossover with Rosario + Vampire and MLP FIM. I think something like this could have potential, especially if Spike goes to Yokai academy.
So, the plot can be one of the mane six or Spike (or all of them) goes to Yokai Academy, or the Rosario team somehow ends up in Equestria.
if you choose the first plot, then who ever goes to the Academy can start from the beginning or when to Rosario team is fighting Kuyou (the Fox guy that leads the safety comity). If the mane six and/or Spike goes to the Rosario world, they must have human forms. Mane six can have the elements, and if only one of the mane six goes, then there element won't need the others to work.