Just thought I'd mention that I'm currently working on designing a used syringe bottle. The bottle and top are separate pieces, with the top extruded separately to allow some jagged edges in it for safety reasons. I had the idea with the basis of more in the 3rd world or isolated areas in the future. It's more for use as a proof of concept, the main issue I'm having is designing a way to lock the two ends together without more than 45 degree overhang (though recent work with the nophead makes it seem like you can have a small amount of full overlap, at least enough for a locking mechanism).
The reason I think this would be useful as a Rapid prototyped object is that these are always needed(esp in 3rd world areas with high HIV rates). And being able to make them easily and cheaply would mean you can print one off in a few hours, fill it once over the course of a few days, then burn it (something you need to do for biohazardous materials anyway). A bottle takes up huge volume for shipping, and being able to make them onsite would mean that aid trucks or planes would have more volume free. plus a special bottle design is still relatively simple but useful at this stage in the project.
I'm still trying to get it all perfected as 3d files, but the basic idea is seen at [
ecx.images-amazon.com]