It's a historical fact that the tribes were moved to the northern borders of Assyria as a buffer against hostle peoples. The Assyrian tablets put that one to rest. Where they put them was up near the Causausus mountains. That's historical fact also. They had several centuries to migrate into Europe and there is evidence that prior Israelites had gotten there earlier from Egypt.
I don't see how it's so improbable. Also I'm reminded of Hosea 1:10,11:
10 Yet the number of the children of Israel shall be as the sand of the sea, which cannot be measured nor numbered; and it shall come to pass, that in the place where it was said unto them, Ye are not my people, there it shall be said unto them, Ye are the sons of the living God.
11 Then shall the children of Judah and the children of Israel be gathered together, and appoint themselves one head, and they shall come up out of the land: for great shall be the day of Jezreel.
Either God is a piker or this is to come to past. So the Northern Kingdom has to be here today and there have to be oodles of them, and they will have to be the same people from the same stock.
That's why I asked if you could think of another candidate then the European/American/Austrailian/New Zealand, ect people. 