Considering revisiting this build with a twist that I found amusing. A Beguiler (magical beast from Shining South) Beguiler. Along with a variation of Korwin's build
http://www.minmaxboards.com/index.php?topic=4039.msg54715#msg54715 from the comments in the Ultimate Magus handbook, this seems potentially entertaining (if squishy as all hell).
Beguiler
Str: 10 (14, -4 Racial)
Dex: 24 (18, +6 Racial)
Con: 14
Int: 22 (18, +2 for levels, +2 Racial)
Wis: 15
Cha: 10
Beguiler 1 / Focused Conjurer 3 / Spellthief 1 / Unseen Seer 1 / UM 6 / [Beguiler +1 (2) / UM +1 (7) / Unseen Seer +1 (2) / UM +3 (10) / ??]
(If I was to bring this guy in to the game right now, he'd be level 11; the rest is further planning)
Extend Spell
Multiattack (can this be taken as a fighter bonus feat at Wizard 1; if not I need a different Combat feat - with a Dex in the twenties, Improved Initiative isn't a no-brainer anymore)
Practised Spellcaster (Beguiler)
Master Spellthief
Persistent Spell (either when he gets sixth level wizard slots or in time to get Easy Metamagic when he gets fifth level slots)
Arcane Disciple: War (add to Beguiler list) - not being able to get past fifth level spells won't matter since he'll only ever get sixth level Beguiler slots; besides Divine Power is what's actually interesting there.
Last feat could be Easy Metamagic or Theurgic Specialist if Dragon 325 is allowed, Residual Metamagic, or Spell Mastery in preparation for Uncanny Forethought. Or Multiattack if I wasn't able to take it at level 2.
Equipping this guy would be interesting, as he's a small sentient animal with a prehensile tail; I'd imagine this will cause some issues with gear selection.
Also, does anyone have an opinion on the value of adding the Dark template (and then buying off the LA)? I'd likely wind up coming in a level lower than otherwise, but those are some nice bonuses.