It may indeed be widespread, I just haven't seen it done where I am (near Houston). I've seen
Lilibeth once or twice, though. As I said,
Beth being the most common
Elizabeth nn here, I guess I thought
Lilibeth must be a combination of
Lily and
Beth; it hadn't occurred to me that
Lili- would be diminutive of
Eliza-. But sure, why not.
And, you're... welcome. :-)