Has anyone ever fitted or contemplated fitting a large roof light in the pop top? Dethleffs fit two humongous ones in the Tourist range & it makes the van so much lighter & airy inside.
We've just sold our M/home which had a 3ft x 2ft tilting/sliding one over the lounge area & two small at 15" square, one near the kitchen & one directly over the shower, they made such a difference.

Automotive Leisure did a special edition with a sky light, my personal view is that I wouldn't be comfortable putting a hole in the poptop as it is not fixed like a standard caravan, the constant up and down movement could potentially cause stress cracks.

Yes, the curve on the poptop of corners can lead to stress cracks ordinarily. Fitting a rooflight could potentially generate even bigger problems. You'll find that in reality, outdoors, in the season the interior is very light due to the canvas poptop sides. This is especially so if you find it difficult to sleep in the early morning light.