Right after LnC ended there were several stories where the characters and the actors changed universes, but I can't remember any of them right now.
There was
SwapMeet: Burbank by Debby Stark and
SwapMeet: Metropolis by Margaret Brignell. L&C find themselves in our world, and Dean and Teri find themselves in the L&C universe.
Wendy Richards doesn't have Teri and Dean - she has "Conor Kane" and "Laura Lindsay" working for "Marner Sisters", filming a Superman TV show, in part one of a trilogy,
Big Boys Do Fly . It's followed by
Big Boys Do Fly II - Close Encounter and
Big Boys Do Fly III - Torn Between Two Worlds . I don't know if this counts, because Conor and Laura are not the real-world Dean and Teri.
For a good fic about Superman really landing in our world, check out Shayne Terry's awesome
Veritas . "Summary: An alternate Clark Kent finds himself flying a planeload of passengers from 1993 Metropolis into real world post-9/11 2008 Washington DC. How will he deal with this new, darker world?" Don't miss this one.
