Dunno how many people here have played The Sacred Stones, but I just found something cool.
FE8 (Fire Emblem: The Sacred Stones) doesn't outright show the player a genuine flag or symbol for any of the nations like some of the other FE's do, but if one were to look at the official artwork for some of the characters, you can find a symbol that would most likely be on a flag for Renais. I have no idea if such a symbol exists for the other countries yet, but I'm going to look into this.
Fado:
It's only half of the symbol, as we are not looking at Fado (the late King of Renais) from the front, but from a side-view in this artwork. However, this image is not proof in itself, as Fado's armor is covered in other symbols.
Seth:
This would be the same symbol in full-view, as seen on Seth's armor. But you say that's not good enough, yet. He may be captain of the Renais Knights, but he's not royalty. Alright. I'll pull up the last two exhibits.
Ephraim and Eirika:
The symbol from Ephraim's armor is to the left and Eirika's is to the right. What is the significance of these two? They are the prince and princess of Renais, and twins at that. But anyway. They are royalty, and once again, the symbol shows up.
It's hard to get a good shot of the symbol, as the best image of it was shown in Eirika's armor, and one has to look closely to notice that it is in a number of other places. I feel somewhat accomplished after finding this, because it's always annoyed me a bit that none of these countries seemed to have a symbol. So yeah, just a bit of a cool fact that I figured I'd share. But then again, I'm easily entertained. So you can just ignore my presence.