It's not all that difficult to make the model yourself. Sugar pine is a nice, easily worked choice of material. Print out waterlines spaced according to the thickness of the wood (say, 3/4"). Cut out some station templates to use in checking the shape. Paper printouts glued to masonite is not a bad way to go for these.
Bandsaw the wood to the shape of the waterlines at the top of each piece, leaving a little margin for sanding, etc. Then carve away the outside corners of the "wedding cake" down to the inside corners. You can do a lot of shaping with 60 grit sandpaper wrapped around an appropriately sized block, or a round dowel to work the concave contours.
I'll bet you can do it in a couple of industrious weekends, and learn a lot in the process.
A school in Seattle builds models this way as an annual project. Check it out at http://www.r-boat.org
-> Pond Model -> Follow the progress of building the boats.
The kids eat it up - sharp instruments and molten metal; Cool!