The arcane gishes I know of (and often helped build) include Dragonslayer1/Spellsword1/Abjurant Champion7, often in that order.
You should stop helping people build gishes then, Abjuration Champion only has five levels.
I'm also not a transcriber to Dragonslayer simply because of the Feat tax, however if you're going that route to maintain full-casting and pick up the Martial Weapon Proficiency
for Spellsword then you actually need to
skip Spellsword. Like a
Sorcerer 6 / Warmage 5 / Dragonslayer 1 / Knight of Thorn 4 / Abjuration Champion 4 may only hit 13 BAB, but on top of actually being legal and doesn't trade a single level of caster progression away. It gets two bonus Metamagic Feats to try and make up the Feat tax, ConMod/day +3/die damage with Spells for increased damage, party buff version of Cha-to-AC, double the ASF ignoring bonus since it clocks in at -20%, can use his weapon to deliver touch Spells, all the actually useful stuff from Abjuration Champion, minor boost to Divination, etc. It's pretty much caster++ in that it doesn't really sacrifice much for melee and gains several caster-related synergies instead of nothing.