So it turns out that Marvel has a whole line of kid-friendly characters under the moniker Super Hero Squad. I like it already! And it gets even better, because I've just found that they also have a Create Your Own Comic feature on their site. It's a full-featured comic strip generator similar to previously featured ToonDoo and Toonlet, but the graphics really set it apart from the competition.
This is pure Marvel. It's beautiful stuff, really. You can either create a comic strip or an entire comic book. I selected a single strip, and I was then offered a number of possible layouts, ranging from the standard three-block strip to the funky layout that you see in the screenshot above.
You then get a palette of backgrounds, characters, objects, dialogue bubbles, and "sound effects" (those are the "ZZZATTP" and "Krunch" above). There are tons of options in each category, except for one. For some reason you only get five objects to choose from and they're all surprisingly mundane: a cellphone, desktop computer, laptop, office phone, and a chair. Yes, a chair. How exciting is that?
Objects aside, you do get many characters and some seriously beautiful backgrounds -- and it's just plain fun.