I don't see why not. The ruling for holding the charge allow you to make a full attack to try to discharge your spell. Just remember that you provoke aoo if you normally would. Unless you're a super freaking awesome magus, in which case you rock. :)
When you cast a melee touch spell, and you don't hit with the free attack you are allowed to make(or if the touch spell has multiple charges), you can keep attacking with it the following rounds to try and get it off.
My question is, do you have to make each touch attack as a standard action, or can you attempt to two-weapon fight with the touch spell, effectively giving you two chance to hit, for a small penalty on that roll.
Additional, can you make multiple touch attacks if you base attack bonus is high enough to allow for iterative attacks?
The question specifically relates to Chill touch, which has multiple charges based on caster level, but i guess it's the same for a touch spell like Vampiric Touch, at least until you hit the first time.
As a non-magus, you can choose to deliver the charge as a melee touch attack, against the opponents touch AC, as a standard action. You can also choose to deliver the charge with an unarmed strike or natural weapon attack against an opponents full AC. This would follow all the normal rules of unarmed strikes (provokes without a feat or ability that says it doesn't, iteratives based on BAB, TWF, whirlwind, whatever).
As a magus, you have all the above options, but you can also spellstrike to deliver the charge with a wielded weapon.
If it could help, I suggest the first part of the spellstrike an spell combat guide: http://paizo.com/threads/rzs2nler?A-Guide-to-Touch-Spells-Spellstrike-and-S pell