seem able to make these:
but then not able to make these:
the way i see it there are roughly 2 dozen car models for sale with both a fixed roof coupe and a convertible body style. in almost every case the fixed roof models have fixed rear windows and a physical b pillar. they already have the engineering of the sliding rear windows and b pillars within the convertible models. The majority of structural improvements and weight in the convertible models are due to the fact that there is no roof. surely just having a roof even sans b pillar would leave these structural improvements uneccesary. additionally in every convertible model the beltline stays the same when compared to the coupe models and all the convertibles obviously passed the crash test. finally in almost all cases the convertible model is never more than 2-3k more expensive over the coupe so im wondering why the pillarless coupe is an extinct creature besides the mercedes and rolls royce models that have it. Get to work auto industry!