I think you can find an implementation of this specification (encapsulation of the OEB format in a container) in the new Adobe ebook reader available in Beta version at
http://labs.adobe.com/technologies/digitaleditions/.
In this new reader, two formats can be read:
- .PDF
- .epub (which is a reflowable format)
Download an epub file from their library, rename it in .ZIP, unzip it and you will find an OEB publication (the HTML and CSS files) .
To make a small summary:
IDPF new spec <=> ePUb <=> OEB zipped