I think you could squeeze a thin flatbed mechanism in there, it looks like the scanner is in a separate lid part (I couldn’t watch the video), and those LIDE scanners have almost nothing in them. Sheet fed scanners are sub optimal for everyday scanning as you can’t do anything other than a plain sheet of paper.
As for the print part, I’d use a full width printhead, such as the Memjet or the HP Pagewide tech. It’s not caught on that much for general use, it’s too expensive for the typical home printer. They have some business models but they were practically giving them away a while back, so I don’t think adoption has been as good as HP had hoped.
With some improvements to the paper feed mechanism, it’s not a totally outlandish concept. I’m still not sure that the roll paper functionality is going to be that useful- Reams of paper are available everywhere. You’d need a 150m roll to equal one standard A4 ream, which is about 3x the length of a normal roll of 80GSM paper.
