Yes, I'm familiar with the motif of the "plot" to ensure that the youngest inherit the property -- just look at all the stories where it's the youngest child who's the only one moral enough, or lucky enough, to pass the "inheritance test."

I've also come across the theory (though I don't know how valid it is) that this element of the youngest, rather than the eldest, is the designated heir is a remnant of the ancient Indo-European culture that was matriarchal rather than patriarchal.