The 1.2 volt cells that are used in submarines are about a metre in height with a very high capacity; the new cost would probably be prohibitive but if they are available after having done their stint in a sub, then they might be a proposition for home use.

The company I gave the link for has capacities from 10a/hr to I think
500a/h was the largest.
The 10a/hr looked to be like a small motor cycle battery.
Anyone contemplating an off grid or backup system ought to give them
serious thought as while they are more expensive you may never have to
replace them, and you can refurbish them yourself if you get a failed
cell by replacing the alkaline.

and if you are using a 12 v system and one of the cells and one cell really fails then only that cell needs to be replaced, unlike composite batteries where a cell failure usually means replacement of the battery.

Helga: Raycom Jardine rehctub your grandchildren are going to say one day, faced with all the evidence how stupid and selfish our grandparents were, they might let you off and say perhaps they were senile.

Your emotive argument fails to convince.