Making this was alot easier than exporting it and getting it in the game, but here we goes.
I went ahead and added emblems to them. I didn't want to just throw a coloured piece of cloth up there so I thought red and blue... red and blue... fire and water. I'm going to redo the wave for sure because it's ass, and probably the flame because I have a better idea. And the side pieces too.
If you want it,
take it. Of course, to use it you'll need to dick around with pak0.pk3 which means no playing on pure (read: most) servers without changing it back. The models and textures in /models/flags/ and the shader with the scripts folder.