AFAIK, no window manf makes one for the compound curve on the front of Scamp or the front and rear of some Bolers.
I have considered cutting a hole in the center of the front plexiglass and installing a flat crank-out window (RV or from a pickup truck canopy/topper) and fairing the windows
together with some custom wooden wedges. The gravel shield should be sufficient to keep road-rain out (I had a similar but larger setup on my previous Jayco 16). The advantage would be to have airflow through the trailer when it is parked facing into the wind (The front half of a Scamp 13' has poor ventilation).
I sometimes regret not installing my fantastic fan with the hatch opening forward to get better air flow. I have recently seen so Euro hatches that can be opened with either end or side as the 'catching' edge, or the whole thing lifted.