Chrisk,
MPV type cars have fallen out of favour with the general public, who seem to prefer SUV’s, hence the demise of many MPV type cars.
However, there is the Citroen Berlingo/Peugeot Rifter/Vauxhall Combo Life which are reasonably ‘new’ to the market or recently facelifted as well as the Ford Tourneo’s which Ford are not dropping. Also as you said a new VW in the pipeline.
So, there should still be a few vehicles around with a high rear roofline, however they can be a bit van-like.
It boils down to the fact that manufacturers generally only produce vehicles that sell in great volume (which means to the general public and mainstream fleet buyers). If they had to design and build a bespoke vehicle just for disabled people to lug wheelchairs/scooters/hoists etc around, the unit cost would be astronomical.
You never know though, just as a lot of things run in cycles, the current fleet/public ‘love affair’ with SUV’s might eventually wain and voluminous vehicles may come to the fore again in the future.
Dave