Over the past year, I've started a number of threads with questions about tramp steamers, Warlord-era China, and other things of that nature, feasting on the fount of knowledge available from the fine folks here. Well, though the larger project of which this is a part has just begun (having this was a necessity to begin it), the part that might interest the boards is (more or less) complete. There's still a lot left to do - cabin interiors and the engine room, mostly - but as those aren't of immediate reference need for me I'll be putting them off. This project has taken me far longer than I'd expected, and I put in far too many hours, but I'm pleased with how it's come out.
I haven't photographed the (nearly) finished thing yet, but I have taken a few process shots. I thought I'd post those and post the finished ones in the next few days.

The basic skeleton. This is all foamcore. The papers to the side are the plans/bluepirnts I made up, and the figure sitting atop it is a fairly hefty one, there for scale.

Here I'm starting to build the lower deck above the engine room.

Here I'm starting to lay in the wooden decks (balsa wood) and I put in a foundation for the mast (a bunch of squares of foamcore stacked with a hole drilled through the middle)

Here you can see the bottom deck foundation.There are two hallways that meet in the middle, with drainage grates at their intersections (plastic needlepoint backing). In the middle, near the front, you can see a hole which is a skylight to the engine room, and the catwalk above it.

Here you can see the wooden exterior decks laid down, and the mast run through the forecastle deck (the mast is a fiberglass driveway marker)

Here's the upper deck foundation (well, the front of it; at this point, the back cabins haven't been boxed in). Originall, I thought to use a vacuum cleaner attachment for the steampipe (pictured here), but scrapped that for a series of connecting PVC pipes for stability. You can see the booms on the table.

Here's a close-up up the forecastle. The balsa wood was all one big flat piece, and I used a ruler and bamboo skewers to carve in the planking detail, and punch in the nail holes. Like most everything else, the details of the mast base are piecemeal bits from Hobby Lobby, a wooden flower pot and spool. Some jewelry makes the rings that's hold the spars (I wanted them to be swingable) and the rivets are put on with puff paint (also known as three-dimensional fabric paint).

Here's the boat's shape, finally realized. The hull on the front, where it curves, is craft foam. I've replaced the vacuum cleaner pipe with pvc.

Here there's a lot of orange. More of that puff paint. It's my most indespensible tool. I use it as caulk, I guess, filling in cracks and firmly affixing one piece to another in a way that looks welded. You can also see the portholes here, which are half of rivets from a fabric section.

With the shape and all the foundational stuff in place, I started on the detail work. Here's the forecastle again, with some anchor chains and machinery. On the mast, you'll notice one of the few non-scratchbuilt items: a small anchor winch from a Revisco kit. I also use a Revisco steering wheel, some of the ladders are Revisco ladders, and the lifeboats use a scaled-up Revisco template. I had the winch on hand (that's why it's painted) and figured I might as well use it.

The shrouds leading to the mast are wire of various gauges. It has a little bit of give, which looks nice and makes it look, I don't know, real.

This part was a doozy. I wanted the cargo hold lids to be covered and battened, and so I individually linked all of these loops to loop-headed pins, cut 'em to size, and glued 'em to the fabric covering the foamcore. Though I didn't take a picture, I put a drop of puff-paint on the top of each loop to make it look like it was bound through the fabric.

Here are the dollar-store airhorn nozzles that I used for the air vents. I cut off the lower part and connected 'em back at a right angle. I used sculpy for the connecting area, and in my foolish impatience held one of the larger ones close to a hot stovetop to try and harden it (I was making tea, and had it in my hand). I half melted the thing, but figured "what the heck," and used it anyway, a big rust spot from where it was clearly dented by something. The rivets are (surprise!) puff paint.

My wife took this of me painting it.

Here's one more, to give you a sense of the scale. It's four and a half feet (54 inches) from bow to stern (1.37 meters for you metric folks)
I'll post pictures of the (nearly) finished thing as soon as I take 'em, which should be sometime in the next few days.
Thanks again for everyone's help!