@ Dentaku: We built a prototype eBook device in the Microsoft Reader group around 1999. It had a 150ppi display, which did, in fact, have the RGB striping running vertically on the portrait display for the very reason you suggest. We had to have the glass specially built for it; all the manufacturers were geared to produce "vertical RGB in landscape" glass.
Technology at that time was not really up to the job. But it got better, fast. The first high-res device display I had was the Dell Axim PocketPC. Anyone remember that? 204 or 208ppi screen (I forget which), beautifully clean, crisp text - especially with ClearType in Microsoft Reader eBook software running on it. As a test, I read Gibbon's "Decline And Fall of the Roman Empire" in its entirety on it. It's a gargantuan reading task, six or seven volumes - and it passed with flying colors.
The prototype we built was at least ten years ahead of its time. That seems to have been the problem for the company.
The Microsoft Reader software was very, very good. If you were able to run it today on an iPad, it would stack up equally well against iBooks or the Kindle Reader - even after more than a decade.
I'm delighted eBooks have now come of age. I just wish...