Like Sam stated above, I don't know of any K-Line D&H RS3's ever being produced. Being a big D&H fan, I'd like to know if there were!
Atlas, on the other hand, did offer one quite a few years ago in their Trainman Line. There was a 3-rail "Conventional" and TMCC/RailSounds-version...and a 2-rail version as well. Click here to see it on the Atlas website.
I own the Conventional version pictured below in its original brand-new condition before I detailed and weathered it.
Hope this helps...and good luck with your search!