I am so pleased with the response to my question - many thanks to especially to JBENNY for showing the problem solved.
The fact is I don't own a reader (I listed Sony because it is the one I will get when it comes out in Australia - because of its price - I am looking for a device that can be used in schools, though the Iliad has features I would very much like to see in use).
I mentioned World Unique IDs because I see absolute references as very important in study.
WUIDs are very easy to generate (contact Lestec.com.au if there is interest in this). The idea is that edition is given one ID and the work itself another. These can both be established via name-space xmlns. It works like an ISB number but can be generated by anyone anytime on the net. If adopted, it means bibliographies and references are unambiguous and electronically chasable.
My aim, long term, is to make quality textbooks available for school students via a reader (ie their complete course references), referencing is an important aspect of this. Ideally epub would have a choice of css stylesheets one rendering paragraph, illustration, picture and tables references, another normalized reading.
In the long term, while epub seems perfect for literary works, I hope the industry also embraces TEI in the future - especially important for university students.
I am looking forward over the next year of getting plays (with line numbers) available. In rehearsals and study the readers would be great, then the same text could be projected or shown on a monitor as a cheap tele-prompter via a laptop.
The future of this technology is very bright, it solves a lot of problems in my area (Photocopy madness, general shortage of textbooks and the poor quality of so many, plagues teaching - a cheap robust reader is a dream come true as I have had to resort to type condensed pdfs
http://members.iinet.net.au/%7Egreg....ld/Literature/ ).
Again thanks for all, as epub now looks like a perfect intermediate technology for my needs.