I'm a passive shipper of the two, I've never read or written anything about them, but I always have this thought that maybe something happens in the lifestream, like perhaps Sephiroth eventually after a long time feels remorse, or Aeris is there to help him understand what he did wrong or something.

Yeah, it would be hard to make work, but I bet it could happen.

*dies* And now I wait to be crucified by people telling me that I'm dumb!

Bring it on!