The only one I could imagine is a FFX prequel, right back at the Zanarkand War time. It would be good, and I get annoyed that FFX and FFX-2 gives you so little info on 1000 years previously, also known as wot started it all. In FFX, the story revolves around Sin, which was created 1000 years ago. FFX-2 revolves around Shuyin, Lenne and Vegnagun, which all came from 1000 years ago. And sadly, they don't give enough info on the 1000 years ago time.