David's full genealogy?

 I was perusing my files earlier in search of interesting Purim info, and came across an interesting tidbit I had long but forgotten. Yehuda Levi Nachum z"l was a famous collector of Yemenite manuscripts. Not long ago, his collection was donated to the National Library of Israel. Some time last year, I think, while collecting sources for a different project (can't remember what it was), I skimmed some of his published compilations of manuscripts. In the volume מיצירות ספרותיות מתימן (Of Yemenite Literary Works), p. 192, he published a genealogy of a man named Yeshuah ben Aharon (ישועה בן אהרן), which included tracing the man to Yaakov Avinu through Yehudah. What was shocking, however, was that the lineage was not the standard Davidic genealogy (i.e., Yaakov > Yehudah > Peretz > Ram > Aminadav > Nachshon > Salmah/Salmon > Boaz > Oved > Yishai > David >>> [further descendants]), as we find it in Tanachic sources and most later Yehudaic-tribal genealogies from later sources, but rather- David is missing, yet the list included a whole mass of other names and generations (arguably way too many):

One might argue that in at least some of these cases there was an attempt to squeeze into the genealogy names of other famous figures from Tanach. For example, about midway we find Eitan and Heiman, who were two of the Levite leaders from the time of David. And we find here apparently a man named Efrat (though in Tanach this is a woman's name), and we find here the lineage of Betzalel - but in reverse. Instead of Betzalel ben Uri ben Chur ben Efrat (= Miriam, who was Chur's mother), we find: Efrat ben Chur ben Uri ben Betzalel. We also find Kenaz ben Otniel, rather than Otniel ben Kenaz. There are many other strange details to be noted. It may not be so extreme to suggest that this is genealogy is a fictional construct, perhaps created by Yeshuah or one of his ancestors, probably for the prestige of having a direct lineage all the way to Yaakov.

However, there's another interesting point to make. While David isn't mentioned here (and it's quite possible that, ironically, a copyist simply missed his name), for all intents and purposes this seems to be a Davidic lineage - everyone else key to the lineage is mentioned. What's interesting about this is that Rasag (Rav Saadyah Gaon) in his tafsir (Arabic translation) of Ruth already proposed the possibility that Yishai ben Oved was not identical to Yishai father of David! Rather, there were two figures - Yishai I was the son of Oved and an ancestor of Yishai II, who fathered David and his siblings (this is one possible explanation for the discrepancy in dating the generations of David's ancestors, given that there were only five generations between Nachshon who was part of the Exodus generation, and Shlomo who built the Temple, which occurred 480 years after the Exodus). For more information about Rasag's curious proposal and a Hebrew translation of the tafsir of Ruth, see here, pp. 11 and 42.