I have, to my great satisfaction, finally settled on a combination I like well enough to sit down and crunch the numbers. I just wasn't getting anything I liked out of having a class in addition to Wizard or Psion, so...you mentioned upthread we could put something from Savage Species in there, so I'm going to be playing an Astral Deva/Wizard.
Character-wise, since your cosmology is so different, I think he is simply the child of a some weakly-godlike Archangel and a mortal. He was groomed from childhood to transmigrate to the higher planes and do abstract spiritual stuff for eternity, but rejected that life in order to screw around the material world, get into trouble, and be an Adventurer(!). He has more recently settled down as head of a University, where he's considered something of an academic rock-star. His history as a tomb-robbing arcanist has made him far more comfortable with casual violence than most sages, and he also suffers from a slight tendency to view life as a game that he plays for fun.
He's arrogant, overconfident, and has total faith that any problem can be solved with sufficient application of magic, elbow-grease, and bullshit.
I am suddenly twice as excited about my character as I have been with any build I've even considered. Awesome, the game finally clicked for me.
Addendum: I am going to pay out for a Lyre of Building and I should have the Fabricate spell. Anyone who wants deep discounts on their stronghold construction can make a big donation to the university fund (I figure we can split the difference on how much money you save. There will also be a plaque! Real bronze! With serifs!)