Who were Eldad and Meidad, singled out for prophecy beyond what their 70 peers experienced? The Targum Yonasan has an interesting spin. Recall that when Pharoah decreed that all male children should be drowned Amram divorced Yocheved, which started a movement that others followed (Sotah 12). It took the cajoling of Miriam to re-unite her parents, leading ultimately to Moshe's birth. Targum Yonasan writes that Yocheved actually married Elitzaphan bar Parnach after being divorced, Eldad and Meided are offspring from that marriage! That makes them Moshe, Aharon, and Miraim's half brothers.
I told this to my wife on Shabbos, and she raised a few objections. How could Amram re-marry Yocheved after she married another husband? (My answer: no problem, the Torah had not been given yet so there was no issur.) How was there time for her to conceive and give birth to two children? (Who knows how long she was divorced?) And doesn't the gemara say that Amram's actions led to a mass divorce movement -- all husbands followed his lead and divorced their wives as well. It doesn't make sense that someone would buck the trend and marry Yocheved. (I have no answer for this point other than to think the Midrashing argue.) Perhaps, suggested my wife, the idea here is to create a thematic relationship and remind us of the separation between Amram and Yocheved as a prelude to the parsha of Miriam's objecting to Moshe's separation from his wife.
My wife later showed me that the Ksav v'Kabbalah quotes that a certain scholar (unnamed) sent a letter to Rav Amram Gaon saying he saw the graves of Eldad and Meided and on their their tombstones is written "Brothers of Aharon from the father but not the mother." According to this story, Amram divorced Yocheved after mattan Torah, as she was his aunt and became forbidden to him. Amram remarried and had two other children named in a way to emphasize that they came from a kosher marriage: Eldad = "aino dodah," not from my aunt; Meided = "mi hu dodasi" who is my aunt. The relationship between Eldad and Meided and Moshe, Aharon, and Miriam in this version is the opposite of the Targum -- they are half brother through the same father. However, the Ksav v'Kabbalah questions the authenticity of this legend. If Amram divorced Yocheved only after mattan Torah, that only leaves two intervening years until the episode of Kivros haTa'avah, where Eldad and Meided became prophets. They must have been precocious toddlers indeed! I also wonder at the purported tombstone engraving. Why mention being brother of Aharon and not Moshe Rabeinu?
The mysterious lineage of Eldad and Meided, their prophecy, what happened to them, have all the ingredients to make a good thriller. Someone get Dan Brown on the phone...
For another insight on the parsha from the Ksav v'Kabbalah, see here.