Israel is actually an interesting case. It was almost created from scratch, if you know what I men. Large numbers of Jews had to move there before it could be a viable ethnic homeland. I can't think of another case like that. However, there are lots of ethnic groups already living in their homelands that simply aren't independent states.
Are there any other ethnic groups that are very dispersed but might congregate if offered a nation-state? The Gypsies perhaps? The Zoroastrians? Arab Christians? (was that Israel's plan for Lebanon?)