Sony has confirmed today that they will not be making another ebook reader - not even for their sole remaining market in Japan.
There will be no PRS-T4, and lesen.net reports that the remaining stock of the Sony Reader PRS-T3 will be sold until it runs out. That device was was launched last fall in Europe but never shipped in the US, so I'm not sure how many people actually have one.
TBH, this comes as no surprise. After Sony first pulled out of the North American ebook market