Agent Boo (Tokyopop): Agent Boo is a series of chapter books with manga-influenced illustrations. The vocabulary and syntax might be hard for a six-year-old to tackle on her own, but it works well if an adult is reading it with her. From the same author as Kat & Mouse. (Three volumes.)

Fashion Kitty (Hyperion): A fashion-forward cat helps other kittens dress to impress. I know, I know… it sounds awful. But the illustrations are cute, the layout is simple and not too hard to follow, and the script is surprisingly good. (Three volumes.)

Korgi (Top Shelf): A beautifully drawn series about a fairy and her trusty dog Sprout. Like Owly, it’s wordless, but the intricate drawings invite conversation and multiple readings. (Two volumes.)

Yam (Top Shelf): Another wordless graphic novel, this one featuring a young boy and his colorful assortment of friends that includes a TV set that behaves more like a dog. The series originated in the pages of Nickelodeon Magazine, and has a loopy, slightly surreal quality about it. (One volume.)

Have you considered the Dayan books put out by Dark Horse? They’re more like mini picture books, about the size of Beatrix Potter’s Peter Rabbit books, but they could work here.

I’ve already sung the praises of Happy Happy Clover — but if she’s already reading Power Pack, what about Card Captor Sakura or Sugar Sugar Rune?

I wish Chi’s Sweet Home was out in English, because that series about a kitten who gets adopted by a young family is totally adorable.

While not manga, Owly by Andy Runton from Top Shelf is great for kids too.

Hope that kinda helps. The difficulty of this task just underlines the point that we need more manga for younger readers. :\

Check out http://www.kidjutsu.com. It’s a website I built for kids to read, discover, and share comics.

At her age, I would recommend Happyloo and Banana-Tail. Any comic rated all-ages should be appropriate.

If she was a little older, I would recommend the Wings of Nibonet, Ebony Box, and Inverloch.