(A note on usage: "Might could be" is a double modal, something which is theoretically valid in American English, but in practice serves as a stigma of lower-class speech; it's somewhat common, for example, in Southern American English, which is my own native dialect, and whose use speakers of acrolect and most other dialects regard as a low-class status marker. Semantically equivalent, but more generally acceptable, alternatives to this double modal might be "…could possibly be…", "…could perhaps be…", or simply "…might be…" -- in this case, "might" can be used to express both modality, thus making "could" redundant, and the further conditionality provided by the adverb, thus making that redundant as well.)

The JPay JPlayer, mentioned and linked elsewhere in this thread, is a cheap ($50) portable device with what appears to be a roughly phone-sized display, 8GB of internal memory, and approval from the US Department of Corrections. It is already being issued in prisons as an MP3 player, for music sold at JPay-owned kiosks installed in prison commissaries, and as a tool for reading email and composing replies which can be sent during kiosk sessions at a cost dependent on the length of the message. Adding to this device the capability to read ebooks, and to the kiosks the ability to sell them, seems like it shouldn't be much of a stretch; reading might be more pleasant on a larger screen than the JPlayer seems to provide, but I suppose prisoners can't be choosers, either.