um Woody (Crossing Jordan) & Sam (Las Vegas) had a long distance relationship for a while. Those two shows crossed over alot.
and Tony Vincent on Casualty was dating Ben Saunders on Holby City, but I dont watch Holby City so I dont know how that turned out.
And in the CSI:NY
episode Manhattan Manhunt, there was some flirting going on between Stella Bonasera and Horatio Caine.