Samus needs a little nudge. How about we get the ladies together, say Zelda, Peach, Daisy, Samus. Now doing what, I'm not sure. That's all I got. As a side note, I'm perfectly comfortable saying I enjoyed Super Princess Peach.
I want to see a crossover game based on Call of Duty first person shooters with the enemies being zombie version that of ever mascot that made it onto the video games scene. Can you imagine getting to kill all mascots over the past 30 years, that frankly you have gotten irritated off. Seeing Mario and Luigi zombified and getting to put some lead into them? That would be cool.
Actually, I won't be going with any mainstream franchises. I'd prefer to go with more left-field but hardcore Japanese games that I feel would benefit from the crossover treatment. First and foremost, Bayonetta / Ninja Gaiden crossover would be incredibly insane and would be well-received by fans of both franchises. Secondly, Vanquish / Sin & Punishment crossover would take the 3rd person shooting genre to the next level. I would love to see both Treasure and Platinum games contribute to development, equally.