One of the things that's tucked away in the Players Manual for ADD is a new cantrip called Flourish. This was actually created in response to one of the players in my own campaign who wanted to jazz up how his character's magic missiles looked. Essentially, it allows superficial customization of spells, with a minimal impact on their utility in combat. So, without further ado, I give you...
Mage cantrip (alteration)
Requires: incantation, gestures
Casting time: see below
The flourish cantrip is one of the few cantrips than can be cast in the same round as a regular spell, for that is its purpose. The cantrip is cast immediately before the spell in question, requiring 6 seconds (1 segment) per level of the spell it is to affect (thus it takes 6 seconds (1 segment) to add a flourish to a 1st level spell, 12 seconds (2 segments) to add a flourish to a 2nd level spell, etc.). Flourish then allows the caster to change the visible effect of the spell in question in some subtle way; a fireball might be purple, magic missiles may have the appearance of golden bees, a grasping hand could look like a dragon’s claw, etc. Under no circumstances can flourish be used to change the actual effect of a spell. Mages and sub-classes of mage will be able to recognize a flourish.