I get it now, i had to give Sanctum another read to actually see the first part since I had only used it to reduce the level of spells. Seems like an excellent solution as it wouldn't require retraining.
Edit: So i took your advise and revised the build, i went with a Focused Specialist Wizard (Necromancy), Mother Cyst, and Divine Metamagic. I know Mother Cyst isn't precisely the best feat but i feel it adds a great deal of fun to the character and the spells it grants access to synergize well with the Spell Focus (evil) requirement feat. With Divine Metamagic Persistant Spell you get to have Necrotic Empower up 24h. I also threw in Extra Turning as the last feat to get some extra fuel for DMM, using Nightstick should work pretty well too.
I included Heighten Spell to boost the DC for Necrotic Cyst mostly, should work quite well with Vestige Metamagic.
Caster levels aren't really optimized but an Orange Ioun Stone would raise Wizard CL to 18 and Ur-priest CL to 19, which could be further cheese'd with Greater Comsumptive Field if thats your thing.
Here's the link to the revised build:
https://docs.google.com/spreadsheet/ccc?key=0AtA7SVl2QqvBdHU5SUNwQXI4a1h1ZTZkRTlxUTRvZlEThanks to Kajhera, Tshern and sirpercival for all your help with this build.