In a post in her lj, Casey hypothesizes that if one were to map Greek mythology to Smallville, an argument could be made that Lionel=Kronos and Lex=Zeus.
I'll agree that Lionel=Kronos, but Lex? Well, let's start at the beginning.
I don't see Lex triumphantly defeating Lionel, as would be the case if he were going to be Zeus. If Lex defeats Lionel at all, he will leave the person we've come to know behind in the process.
But really, I have an awful feeling that Lex will end up being the Lex Luthor II of DCU continuity. The original Lex Luthor, who, you know, killed his parents for the insurance money, used that money to send himself to college, became an engineer, and built up one of the world's most formidable conglomerates, cloned himself. He then had the clone's brain removed and his own brain put in the clone's body to avoid dying of cancer, and passed himself off as his own son.
And I think a parallel can be drawn between Lionel taking Lex's body for his own and eating his child.
So, if Lex isn't Zeus, who is?
Having seen what he did to their previous five children, Zeus's mother, Rhea, smuggled the baby Zeus away to keep him safe from his father. Upon reaching adulthood, he returned, slew his father, and set his siblings free.
Lillian found Julian's body. Julian's death may well have been a smokescreen to allow her to send Julian into hiding to save him from what she saw Lex going through.
So, which of the Olympians is Lex?
Discounting the girls, lavender wardrobe and feyness notwithstanding, we're left with Poseidon and Hades.
My money's on Lex=Poseidon.
Poseidon is king of the sea and was of pivotal importance in the Trojan War. He was sexually promiscuous, and was, well, moody.
Lex is also associated with water, having, I'm not sure whether to use the term "drowned" or not, twice so far in the series, in the Pilot, and in the summer of 2003.
So that makes Lucas=Hades. Unpopular among his siblings, he has a helmet that makes him invisible (and as Casey pointed out, Lucas did disappear at the end of Prodigal).
And when we first meet Lucas, it's in a dimly-lit gambling den replete with shades of red and black.
I wonder who'll be Persephone . . .