The comic books/graphic novels catagory has to be the most interesting part of this story. This is the first I've heard of comic books being supported in the ibooks app, as opposed to using a seperate app for them. I think buying comic books directly from the ibooks app is a great idea, and hope they look great on it, although I'm unsure if the epub format can display high resolution, full color images.
Epub supports high res color images just fine. I've done tests with comic book images using svg also and they look awesome. Sure would like to know how independent publishers can get going on producing these epubs (ie: for comics; what's the best size for the raster images, etc.)! How do I get my books in the iBookStore?! Apple! Answer me!