The problem with electronic text is that it lacks the spatial character of a book. You don't really know where you are at in a giant, monolithic column of perfect text, especially when resizing it changes where text is located. However, in a book, you have several spatial cues that are constant: which page, which part of the page, how deep into the book (depth) and any imperfections on the page itself or with the text. So, with ebooks, how can you duplicate this effect?
One could write a program that lays books out so that the book is more like a book (there are cues that indicate depth, etc.). With svg you could easily add certain permanent imperfections to the text to give it more character.
There are two other ways to add a spatial dimension to reading text:
1. Layer text, or pages, into a 3D landscape. If the pages of your book traversed an interesting cityscape, room, landscape, or mountain path, etc., you would have spatial anchors upon which to peg the text.
2. The page itself could link out into either auto-generated or user defined images (or text). In this way, each page is given visual character that links it to other ideas and images.
IMO, both the ideas and the implementation of these ideas (i.e., embedding pages of text, with textual imperfections into a 3D landscape, or adding pictures and text to the pages of the book itself, etc.) are obvious and trivial. Any college student taking a web or 3D design class could do it. It merely remains for someone to do it.