The day/light cycle doesn't really have a fixed time, so technically it wouldn't be possible.
It's more than possible; I actually made a daycycle based "clock" for my server editting Port's daycycle.cs resource to have 24 hour time along with 12 hour time. Port's daycycle.cs resource will be a good start to making one; it's what I used.
Of course this is possible. But OP didn't actually say how this clock is supposed to work. Print bricks? A bottom print? ...?