I feel like it's asking a bit much to have to supply the characters and action on top of the dialogue. Sure, maybe if we were at a CON and had years of cartooning skills under our belts, we might scribble some characters & ideas, here. Assuming that's still the concept with these?
That said, sometimes dedicated projects have style sheets, character templates and that sort of thing that make stuff like this a lot simpler. Head on over to the Evil Empire and check out the "Donald and Hobbes" community, for example.