as for hackable device; we don't intend to release the magic sauce that makes the latency goes down. what I meant with hackable is that I've wanted an e-paper device which I could run my own code on, without having to look for security holes in the software running on it.
but again; we can't promise anything at this point wrt. hackability; we have limited time and resources, and our focus is on making the device as good as possible. our focus is not on making an open source device, we're not going to release the gerber files. :-)