A third online graphic novel I've found which I found inspiring for my own project is Burn Notice.
It's interface is like any comic book printed on paper. It was annoying to not get to the next chapter right away, but I actually had to click a few times to get there. But I liked the art even if it was more of a traditional style and appearance; or maybe that is why I liked it.
The other two grahic novels reviewed are found here and here.