This thread certainly cooled down my will to buy this DR1000S. 3-5 hours of reading? Ok, it makes it useless as a portable device. But with this size, I think no one was really thinking about it's portability.
iRex made it clear this was a business product. I guess they think that "business" happens in offices, with a computer available where the DR can stay plugged.
It's still not that bad... Instead of reading in a monitor, you can read in a eink screen near it. Just don't think about seating in a couch or in bed for reading.