Back after a very long time, but still with the same question bugging me, a question that re-emerged after having re-read LOTR recently: years ago I posted a thread on the descent of the house of stewards and their supposed royal blood (as quoted in the post below, Hurin is said to be ultimately of not only high Numenorean descent but also of royal blood):
http://forum.barrowdowns.com/showthread.php?t=12358
Now, whilst this did clarify some issues, I a curious about the following: seen the fact that progeny is scarce amongst those with Numenorean descent, and even more so in the case of the royal family, I was wondering whether one cannot pinpoint the descent of this house to certain specific individuals in the line of Elros, but before Numenor was destroyed.
I don't know how cannonical this pdf is, but it might be helpful for a start:
http://lalaith.vpsurf.de/Tolkien/Dynasty.pdf