In a recent article in DigiTimes on August 7, 2008 Epson state that they are still working on their own ePaper, and plan to offer a much higher resolution than the current (PVI) offering which is around 160ppi.
Here's the full-text
With worldwide e-book display shipments are expected to rise at a remarkable 161% compound annual growth rate (CAGR) through 2012, up from 150,000 units in 2007, the thin, energy efficient and environmentally friendly characteristics of e-paper have attracted players such as Prime View International (PVI) and Epson to join in development of the technology.
While PVI developed e-paper is currently used by Sony for its e-book products, Satoshi Nebachi, Epson's general manager of advanced product development department indicated that Epson has developed an A4-sized 13.4-inch e-paper product that it showcased at the Society of Information Display (SID) this year, but the company has no actual time line for further development or shipments due to low yield and product reliability issue.
Nebachi noted that because Epson plans to increase e-paper's dpi from 160dpi to 300-360dpi, the technology needed to produce e-paper on plastic substrates becomes more difficult in terms of volume production and reliability, and Epson has not yet started volume production. Nebachi added that once the company enters volume production e-paper will first be used within the company as an alternative to copy machines or printers, and then product will be targeted to the end market.
Epson is also developing larger size e-paper and color e-paper, Nebachi mentioned that color e-paper still has quality issues, and he estimates that it will be another 2-3 years before mass production.