I'm sure it's been done before, but the search function doesn't work.
I started making a list of characters who'd be cool to use in a crossover, figuring it'd come in handy since i'll have to make something sooner or later in class.
Here's what i came up with right now:
Don't say something like "But [Character name] isn't manly!" if you haven't read/played/watched the original.
Of course, sweating testosterone and carrying big guns is not enough to qualify.
Looking forward to seeing other peoples opinions and additions.