what i think of as undershooting or overshooting is relative to the range... and besides that, what is wrong with clamping? its how computer graphics has always had to deal with these things... limited range simply doesn't exist in that context, and it doesn't harm anything.
when computer games are forced into limited range for consoles you don't get these unless your tv is applying one of those god awful filters that ruins everything anyway... (i'm still not sure why so many tvs have these - reference monitors never do anything this insane) ... but i can tell you what you do get, a subjectively /and/ measurably worse quality of image than from a monitor.
(i don't think i'm alone in this based on the contents of the ITU-R BT.2100 either... which defines a full range as well as a 'narrow' one)