Next step, finding an ebook reader that works on the Nintendo DSi now that I have System 1.4 because that killed the previous reader I had, a basic effort called DS Reader that has had no development for years, only handles plain .txt files and doesn't work with international characters like é and ß for instance. Lo and behold, DSLibris comes to the rescue (second pic), with an author who is interested in pushing further, so it supports .epub, .otf fonts (OpenType) and uses the DS held like a book. It doesn't handle .epub files with multiple html entries in the manifest very well yet, yet being the operative word, and some of the translations performed by calibre have had questionable results in DSLibris, but I'm not sure yet whether that's down to DSLibris or calibre since that's also in beta. Best of all with both, they use the Trac system for bug reporting, which means that the bug reporting and feature requesting system is completely open.
To my mind there are two real obstacles to making the DSi a Kindle for those with more sense than money. One is for Nintendo to allow access to the SD card on the DSi through a more open SDK, the other is to allow better third party access to the DSiWare shop and it seems progress is being made on the second front at least: http://www.nintendoworldreport.com/newsArt.cfm?artid=19854.
An exciting time, but more and more we see Nintendo holding back innovation.