|Well, I can't post links quite yet, but it's broken because it uses practiced spellcaster (I think it's that feat) to attain the requirements for prestiging as a daggerspell mage, something I found out is misinterpreted with the wording of the requirements for the class and the description of the feat.|
Consider adding two levels of Unseen Seer (Com. Mage) for another 1d6 sneak attack, +2 caster levels, advanced learning (Divination) and free silent spell feat; the skill requirement should be easy to meet between rogue and daggerspell mage levels.
If you can spare a feat slot for Combat Casting (Rapier proficiency of Rogue satisfies martial weapon prof requirement), Abjurant Champion (Comp. Mage) would be a strong choice; +5 BaB, +5 caster levels over 5 levels, together with goodies like Extend / Swift Abjuration.