7 Most Wanted Gaming Crossovers

Dealspwn writes: After looking at the insane mashup that Sega, Namco and Capcom have put together for the upcoming Project X Zone on the 3DS, it got me thinking about other gaming brands I'd like to see pushed together. These could be games pitting legends against each other in a fight to the death or something involving them working together. Publishers and IP owners can be very protective over their brands, but here's a selection I think would work well together given half a chance.