I thought that with a bit of work the Commissar might be quite good - not as Smith himself, but as a sort of Warhammerised version. With that, I de-skulled the model, so he'd look more like a Victorian and less like a Nazi, and added some arms from the excellent Tempestus Scions kit and a sabre that I cut from a sprue of Waterloo-type people (goodness knows where I got them from).
Then it was just a matter of painting him. It made a change to be painting an SF model in bright colours, but there's a hell of a lot of detail on this chap, and it took ages. Still, I'm pleased with the result, especially his face. He isn't Space Captain Smith, but if there's a Rogue Trader Smithius out there, this is him.