I would *love* a crossover with Lois & Clark and Scarecrow and Mrs. King or with Lois & Clark and Remington Steele.
In that case, if you haven't read them already, I refer you to the works of Elaine M. Gustainis on the Archive. Her first story,
By The Light Of The Silvery Moon, is a mega-crossover with SMK and three or four other shows, including
Remington Steele, though some of the connections are second-hand at best or really only cameos --
The X-Files, for instance. Still, they're good stories.
Phil