There are a few options here.
- The Duskblade (Player's Handbook 2), as @Egi pointed out, is probably your best bet. The 13th level ability is probably the least restricted form of "spell channeling" that exists. Not only does it allow you to cast a spell as part of a full attack, you get to affect multiple targets too. Normally limited by the casting progression of the Duskblade class, it makes a rather good Gestalt.
- The Enlightened Fist PrC (Complete Arcane) can channel with Unarmed Strikes.
- The Raumathari Battle Mage PrC (Unapproachable East) has a version of the ability, limited by both spell levels and uses per day.
- You have discovered the Daggerspell Mage PrC (Complete Adventurer) already - limited by daily uses and weapon type.
Then there are other options that allow you to channel spells, but do not combine well with a full attack:
- The Duskblade's 3rd level ability
- The Ordained Champion PrC (Complete Champion)
- The Spell Storing and Bloodstone weapon enhancements (Dungeon Master's Guide and Magic Item Compendium respectively). The latter works only with the Vampiric Touch spell, but it empowers it for free!
- The Smiting Spell metamagic feat (Player's Handbook 2)
- The Spellsword PrC (Complete Warrior). Beware, it's a rather cruddy class overall, mentioned here for completeness.
- The Havoc Mage PrC (Miniatures Handbook). Beware, it's awful!
Finally, keep an open eye for anything that allows you to cast spells as a Swift action (such as the Circlet of Rapid Casting from the Magic Item Compendium and the Quicken Spell feat), and swift action spells in general (such as the Wraithstrike spell from the Spell Compendium).