I believe there are already some TVs that accept 48Hz as an input frame rate over HDMI. This is the only way 48fps video will look right, unless we move to 240Hz (the LCM of 48 and 60). 120fps would give the same juddery results as playing 24fps on a 60Hz display, but going up to 180 might be good enough to make the judder invisible (I don't notice the judder of a 24fps stream on an 85Hz CRT, but do at 60Hz, for example).