While I'm not SCRA player, from my viewpoint they're heavily militarized and have too many targets to allow their emissaries to fly in liners. They prefer simplier and more powerful things.
I'm sure sometimes envoys will have to resort to guns diplomacy too, so liner won't work.
Sorry to say, but I don't think this model is neccesary. With proper texturing it could replace slave liner, though.
