Hey again,
Well, his bile acid levels came back just the slightest bit elevated. The vet doesn't think they're high enough to be symptomatic of a shunt. So...she said to just monitor him for the rest of the week and see how he feels/acts. I guess its a relief that he doesn't seem to have a shunt, but I wish there had been some definitive reason for having the seizure.
I'm exhausted tonight...*sigh* Thanks again everybody, I'd probably be a basket case if it weren't for all of you.