Too bad Seeker and Thaumaturge are TOME CLASSES, and not meant for play with regular D&D. Not to mention, they aren't WotC, unless I'm sorely mistaken. And let's not forget the Book of Erotic Fantasy being contested turf... Still, an Uncapped Orb of Fire with all of the above (assume CL 20, for convenience, but we'll have it much sooner than ECL 20. ECL 14, at most.) would be dealing 120d6+1200 or so. Shiny.
That said, if you miss on even one roll, and they have the Spell Reflection ACF, you're toast. Literally.
If said DM is allowing all that, he's sure as fuck allowing Wings of Cover

Don't you just LOVE Divine Defiance? I've been known to use it to Counterspell any and all such defenses with my Sorcerer Gish. It's so easy to kill your prey when they can't cast anything decent.

I'll have to look into that, for sure. My current project now is getting the same caliber of blasting we have here without Tome material. Incantatrix seems a shoe-in, as does War Mage of course. It could most likely also fit SWS if it wanted, without all the Seeker levels, but when we can always remove the save, why bother

AoE burning>single target, after all. Also, this puppy has like 3/4 of the needed components of an LCB, and the means of doing them all day long. So why not

After I finish eating I'll post up a new Tome-free version, though in terms of raw power, the Thaumaturge really takes the cake.
EDIT : Damn quote box misplaced the reply...