I'd only be willing to work on another comic if the concept was interesting and (obviously) pandered to my interests. Even then, I'd only be willing to work on short form comics - knowing me, I'd lose interest or my hype would fade if it was a long form comic.
As for stories that are 100% my creation, I definitely would and am! As much as I'd like to give more attention to one story over the other, it'd feel unfair to my subscribers that are following my current longform comic if i should put that comic on the backburner in favor of the more recent one. So it's just slowly building up a big buffer for the other story, as it hasnt been posted anywhere yet, while making sure the buffer on my current story doesn't run out >>; as for what motivated me to keep working on two long forms, I just like my characters that much lol. not to mention I dont work any kind of job beyond commissions here and there, so I've got plenty of free time.