The problem I see with it is that, AFAICS, one of the reasons it doesn't currently do it automatically is because it'd waste a lot of writes to the flash that stores that info.

Maybe it could be done so that it keeps that data in memory while the empeg is on so that it doesn't waste those limited writes, maybe with an option to save them somewhere. I think that the empeg could probably do with a screen for such stuff when the ignition is turned off, but still has power, that would time out after ten seconds or so.