We've seen it develop from a flexible, skeletal e-ink display into a stylus-friendly prototype and finally, Sony is now ready to sell its digital paper slab -- you might just have to save up a little more. A 13.3-inch touchscreen E-ink display is a pretty rare occurrence and, perhaps because of that, it's attracted a wallet-slamming price tag of 100,000 yen (that's just over $1,000). It'll go on sale in Japan on December 3rd, with a 1,200 x 1,600 resolution e-ink screen and WiFi connectivity crammed into a 6.8mm thick frame that weighs 358 grams. For the sake of comparisons, it weighs less than an iPad air, even if it costs roughly double. Sony appears to understand the cost issue here, because, at least for now, it's spinning the slate as an ideal "digital paper solution" for highly specialized businesses and (presumably well-monied) colleges. It's even thrown off some example situations where financial (or term) papers are uploaded from either a PC or the digital paper device itself, and downloaded for individual reading or scribbling on elsewhere. It also uses E Ink's Mobius display which uses protective film rather than glass, which Sony says will make it easier to write on compared to existing tablet-stylus devices, although we wouldn't go expecting any Gorilla Glass levels of defense against keys and pocket shrapnel.