HI there Ben, probably i'm not the first to come up with this idea, but here is it:
What about a smart cradle. A Cradle that can inform baby's temperature (maybe with an infrared sensor), motion censoring (when a baby is wake, he moves a lot) (3 or 4 pressure sensor spreaded underneath or embedded on bed sheet) and humidity sensor for ,well.... if he get wet 
.
So, we setup thresholds for each sensor, and some how when we got this values, an alarm should ring in parents room.
This is it.
Thanks