: Can anyone think of any passage that explicitly excludes Ruling Ladies? For example is there a passage saying that Narsil or the Sceptre passed from father to son in direct descent over two ages? That would exclude Ruling Ladies.

: If Ruling Ladies are not explicitly excluded then I am tempted to put at least one of them on the list.

I don't know if this is the sort of information you are looking for, but just for the record, here is a tidbit I found. Hope it helps:
In Unfinished Tales, Aldarion and Erendis, I found this:
For the record, this is stated, not as law, but as inherited custom, and there is a note referring to Appendix A in LotR noting that Tar-Aldarion changed the laws of succession in Numenor for reasons of private concern, rather than policy, and out of a desire to defeat Erendis.
...according to custom the Ruler's eldest son inherited the sceptre. It was understood that if there was no son the nearest male kinsman of male descent from Elros Tar-Minyatur would be the heir. After the change by Tar-Aldarion, the eldest daughter would inherit the sceptre if there was no son, and she had the right to refuse. Then the sceptre went to the nearest male kinsman, whether by male or female descent.
Furthermore, it was ordained by the Council that an unwed female heir must resign, if she remained unmarried beyond a certain time and could only marry within the line of Elros or cease to be eligible for the heirship.
Supposedly, Tar-Aldarion also later did away with the provision concerning an unwed female heir.