As fascinating (and time-consuming) as the forgoing ideas may be, they all have a fundamental problem: they are opposed by the simple facts of history and inspired Scripture. History and the Bible indicate that although the tribes were separated during the civil war of Israel, the separation was neither complete nor ongoing. Passages in Scripture indicate that, in reaction to idolatry in the north, many from the Northern Kingdom migrated to the Southern Kingdom to join with Judah and Benjamin. Moreover, after the Northern Kingdom was taken by Assyria, the Assyrians themselves were overthrown by Babylon. This makes it likely that when the Southern Kingdom fell to Babylon, refugees from both Kingdoms intermingled in Babylonia. Thus, in the return of Israel following the Babylonian Captivity, all the tribes of Israel were involved. This fact is attested to by numerous passages in the NT which identify persons from among the supposed ten lost tribes who were not lost, but found in the land of Israel.
If you feel that Anglo-Saxons or any other gentile race makes up the lost tribes, may I say to you, you are very much lost in the maze of Scripture. You may be lost, but the ten tribes are not lost. . . . When anyone tries to say there are the ten lost tribes today, they must be on an Easter-egg hunt.1
1 J. Vernon McGee, Thru The Bible Commentary (Nashville, TN: Thomas Nelson, 1997, c1981), Zec. 7:3, Mark 2:15.