OK, it's been a while since I spouted a theory, but I'll just throw it out there. I'll assume that history doesn't repeat itself exactly, ie. that last Third Age the Dragon Reborn was really Rand Al'Thor. If differences are possible, perhaps Ishamael was a Dragon that failed in his epiphany. (However that'll work out with there still being a world I haven't quite figured out yet.) Possible "proofs": All the above, plus his seeming obsession with TP; He has become darkness himself. He thought himself the DO, and Rand (possibly) associates himself with the Creator. One more point: at the end of ToM, the Dark prophecy references the Lord of the Evening. Perhaps Ishamael, as a mirror to Rand? Just thinking