Don: In perusing the comments received on your original post, I believe I see two somewhat separated markets for a GE style steeple-cab engine. One, of course is the standard, cataloged production GE 45 ton unit used by interurban lines all over the country. ( On the Chicago North Shore & Milwaukee, they were called "pups" and were often MU'd with as many as three units together. This might be a terrific excuse for a prospective buyer to purchase more than one engine.) The other variation, of course, was the heavier duty and somewhat larger steeple cab like the Milwaukee Road or the copper mines in Utah used. i understand that these were rated at 80 tons and "sat" higher off of the rails due to a higher lower cab extension. As I mentioned earlier, I believe that a production model of the GE steeplecabs could be designed to be offered with or without this extended cab, simply by making a piece that can sit on top of the frame with the bottom of the standard cab fastened to it. Should give you the "heft" that you're looking for and also should be able to be painted with the cab and the extension together, leaving almost no parting line between the two sections.
If they were offered, as such, I'd be in the market for a pair of the "pups" in North Shore colors, of course, but also one of the larger Milwaukee Road steeple cab switchers that you're familiar with. Incidentally, I also own one of those imported, brass, Japanese made W-B steeple cab electrics like you show on one of your photos. Mine is still in two-rail configuration and I don't plan to run it on my layout because it just isn't quite correct for the MR operation. Neat little engine, though, and I do recall them on the Chicago South Shore and South Bend RR. In fact I have a whistle from one of them. Had the headlight, too, but it got stolen during one of my personal moves.
I would like to see you go ahead with your project and bring to market both versions of these prolific little locos. Be a great time to introduce them at York next month. Are you planning on being there?
Paul Fischer