I've seen something of this sort done for my mother's family name--Sweeney. I've seen the derivation of Sweeney from MacSween and so forth.

I've read that after Bannockburn many of the MacSweens left for Donegal where they became Sweeneys...that's seem pretty straight-forward. But those that stayed somehow became MacQueens and/or MacEwens. Do you have any idea how MacSween becomes MacQueen or even MacEwen?