Thanks for the suggestions.
I lack the dead-trees books for Shadowcraft Mage and Shadow Adept, and acquiring them in alternate mediums is proving difficult, but I'll keep trying. I've heard amazing things about Shadowcraft Mage and I would like to try it out. Race requirement could be an issue, but if I can acquire the source for the class, I'll inquire whether it can be waived.
Recaster I've seen and it
is nice, though I'm loath to slow down my spell access by giving up levels. Adding a couple more spells known does appeal to me a lot, but I don't know that it's worth giving up caster level and a bucket of skill points, particularly given that I'd not be gaining full benefit of that 4th level what with only knowing 1 metamagic feat on the given list and not really being interested in the others. Then again, a lot of my skill checks can be boosted or obviated by my spells....
If the DM will waive the racial requirement, I'll consider it.
Maybe I'm dense but I'm not seeing a lot of benefit in Ultimate Magus (compared to the cost of lost levels) for a character like this, unless you're thinking use some shenanigans like taking the Arcane Preparation feat and using beguiler as both my arcane classes for UM. Clue me in here?
You've got a point about the damage bonus from Unseen Seer and Hunter's Eye. I had been intending to keep a couple wands of one of the lesser orbs handy and use that as a delivery system for sneak attacks when inflicting damage in combat was necessary, but it still may not be the greatest use of class levels. The boosted caster level on divination interests me, and more so if I end up losing a level to recaster, but I could potentially go a different direction too.
I had been intending to make use of skill tricks, but figured I'd work out which of those to use later. Thanks for the start on those.
This certainly bears some more thought...