I am new to shapeways, having used Ponoko for a few years. I have been using 2d laser cutting for many years, and now just getting into 3d printing for last 3 months or so. I am considering using 3d printing for the barrels of fountain pens, usually two are needed per pen. They need to be fairly light in weight, but attractive. So, the steels are probably out. What materials would be candidates? How about the alumide?
Perhaps the polished Alumide or WSF? Both are porous, so you'd need to coat them with something so they don't collect dirt. If you want a nice "final" product feel I'd go with a detail material or sandstone.