>>A lot of the churches built in the last 20 years were not built with this possibility in mind. I know a lot of the churches around my city aren’t built to accommodate kneeling at Communion. They would all have to be retrofitted for this. <<
Not at all.
Our church building was built in 1985. They would not allow us an Altar Rail. Father set up eight kneelers across the front. One person in line kneels down, next person in line kneels down while the first is receiving, the first person stands up and is replaced by another in line.
Four stations of Priests or EMHCs and our Communion moves pretty quickly.