Obviously the layout could use some work; there’s no longer any default margin added by the ereader, so the text bleeds out. Also my 600×800 dimensions don’t exactly match the iBooks aspect ratio, so there’s more fake book border. But you can see how this could be improved.
Note that the vast majority of EPUB books should not be formatted this way. This isn’t a one-way ticket to CSS Town. If the text on a particular XHTML page overflows the bottom of the single page, it will get cut off. You cannot mix fixed-layout and reflowable pages in the same EPUB file.