Hmmm, I couldn't locate the RAW answer to this one: are there rules that state how one can affect an unwilling target with a touch range spell? Can one make a melee attack in the same round as casting? That would be with a concentration roll for the casting, but any more penalty to the unarmed attack roll?
What about an enchanted, handheld item (sword) that casts a corpus spell on a forcefully hit target? Could one just roll attack as for a normal armed attack?
As I understand it, and the combat rules are squirrelly, you cast the touch spell and at that time make a "melee attack". That is, you use the melee attack rules, and if your attack beats their defense, you've touched them. No extra melee damage is done, because it was not a melee attack, just using that mechanism.
True, LadyPhoenix, but I think that would require Fastcasting the spell. I missed the enchanted sword the first reading, it would be a normal attack roll, unless it had some weird trigger.