Can I ask why you put so much store by user changeable batteries? It's going to limit your options very, very severely, and you're not going to get any "fairly well known e-readers" in that category. There are other ways of charging an eink reader when you're out of range of power for an extended time (remembering that we're talking weeks here, not hours or days), like a solar USB charger.
ETA: danicca was trying to type "Pyrus Maxi". 8 inch but low res 'Digital Ink' screen, 4G on board, micro SD slot. 309 g, 149 euros. No idea what the support is like. No evidence for user-replaceable battery.
Last edited by meeera; 09-04-2013 at 10:21 AM.