I don't know if anyone has done this, but how about a Ranma 1/2
-'You Got Mail' crossover?  Just couple up any two Ranma 1/2 characters
that hate each other as in the framework of the movie inserted into the
Ranma series. The only pairings that I see that could work this way are
Ranma/Nabiki, Tatewaki/Nabiki, Ryoga/Ukyo <--(a stretch, I admit. (since
there isn't really open hostility between them) take an artistic liberty),
or possibly Mousse/Akane <--(Hmm...).

Er, how? 

I'm serious here.  Who in the Ranma cast would use e-mail?  Certainly not
most of them, even if you decided to advance the timeframe of the story to
the present day, for what could e-mail offer them to further their
interests?  There is neither a Jusenko ML nor an alt.rec.chi-blasts, no
one is looking for a new relationship ('cept maybe the extras) And even if
they *did* have the inclination, who would have a computer?

Perhaps the story could be changed to one using traditional mail, but then
how does one get around the fact that the return addresses are printed on
the envelopes?  I might see Shampoo/Cologne/Mousse-Someone Else, since
it's less likely that someone would recognize a Chinese address, and the
return address might not even be an issue if relativers at the village are
forwarding Shampoo's mail to and from her pen-pal. It's still kind of
farfetched, though.

Ryouga recieving mail in any form has it's own obvious problem.



-Natsume Ranma Ranma
-------
The sardines weren't worth the trouble.  A few more shots, then 
Ryoga-san would overheat and explode.  Ducking around a corner, 
I managed to lose him as I entered the ramshackle residence of 
my Anime supplier.

One look at his face and I knew that I was betrayed.  "Tell me."
I insisted.  He refused, so I slammed him against the wall.
"Last chance.  Where can Ranma-Ranma find good fanfics?"
"Try Jason Liao." he whispered, before he slumped to the floor.
I heard the sounds of a door splintering as I left through the 
window, one step ahead of Tendo Heavy Industries...