I've had a couple of requests for material recommendations from guys wanting to have parts for the Y printed at Shapeways. For the armature parts and fuselage shells the best material also happens to be the cheapest, what Shapeways calls "White Strong and Flexible" also know as laser sintered (melted) nylon. The create these parts a very fine nylon powder is spread out to about the thickness of a piece of paper, a laser beam fuses together areas of the powder into a solid, then another layer of powder is spread over it and the process continues layer by layer until the parts are done. The end result is a very strong part with a slightly sandy surface texture, about like that of a sugar cube. It's the cheapest of Shapeways materials because a hole bunch of parts from different orders can be combined into one build volume and the clean up process requires the least amount of labor on their end, just pull the parts from the un-fused powder, blow off and ship. Even though the name says "Flexible" the parts are really rigid and very strong (depending on thickness).
The parts made of Black Strong and Flexible start out white, and then are died black after being cleaned off. There's no reason to go with the black other than it looks kinda cool. black parts a dollar more each.
You'll want to stay away from any of the polished Strong and Flexible materials. Again the parts are all printed the same way, then they are tumble polished with ceramic abrasive medium in a vibratory polisher. This smoothes the surface but also slightly rounds all the sharp corners.
WSF doesn't sand particularly easliy. As it is nylon it tend to gum up easily. But you can get a nice finish on parts by using a hi-solids Primer Filler and then wet sanding with 220 grit wet or dry sand paper. Since the fuselage shells get covered about 80 to 90 percent with model parts you don't have to get a perfect surface. The mounting block and nacelle cores don't need to get primer or painted at all.
One thing to be cautious of with the WSF materials. Occasionally parts can come out of the machine slightly warped. This can happen for a couple of reasons. the first is breaking apart the block of nylon powder with the fused parts inside too soon before everything has cooled. Hot parts are still a little wiggly and can warp if they cool un-supported. The second reason is if thin parts like these are packed in the build volume near thick parts. The thicker parts take longer to cool and this can effect surrounding parts. Warped parts are almost impossible to correct. You can put them in a lower oven until soft, reshape and they will reward as they cool. One of the reasons Shapeways' prices are so cheap is that they minimize labor and so quality control can be spotty. It's better now but not always. I recently had some larger parts printed for an architectural model that were badly and obviously warped. It was a nightmare as we didn't have the time to get them reprinted.
Seriously, I agree with Joe, they're beautiful and I want to do them myself. I completely grok your design philosophy and didn't assume you had any intention of revisiting them. 
