I used to work for the largest manufacturer in Europe, it is available in any length you require, in any grade steel, stainless and aluminium.
Lengths were nominally 6100mm long. To change a machine and set it up looking around 4 to 5 hours, so has to be worth while considering the one Italian machine could eat 1800 tonne in a few days.
Redman Fisher used to have an offcut department in Tipton they re the main manufacturer still and supply other flooring and fab places. Sure offcut dept went when i did along with handrailing, stanchions, fab and steelwork, that was passed over to two group companies one of which Eurogrid in Telford.