Jamie-
Not sure if you could use this software, but hey, it's free...I've used it to write text in realtime. If you play with the settings I'm sure you could get close to the effect you're looking for. Of course, don't let it stop you from learning masking techniques. If nothing else, it's fun to play with. I recently used it in a first year montage for my granddaughter's birthday party.
http://www.wondertouch.com/gloodle/gloodle.asp
Vin