Transparency in a flag? In web it will be just a blue dot on any background (including blue). It also restricts the number of materials it can be made of.

Plastic?

I suppose that's realistic.

Interesting. Certainly makes for some good pictures, but it works pretty badly in electronic representation.

Why not go with the "pale blue dot in a black void"? The symbolism is pretty good, though I guess most people wouldn't want to use a flag that is mostly black because of the violent connotations.

Flags didn't do much for us so far.

Japan looks at the whole-world flag...

We already tried that. You guys didn't like it.