I have just finished the automation of a machine that makes those style of cages but up to 1500mm diameters, with formed collars if required.
The welding is automatic (up to 3 welds a second)
The machine was built as a one off by a machinery workshop for a concrete pipe manufacturer.
There are machines out of Germany and Italy (the italian ones are a poor rip off of the German designed machine) but these will cost you nearly $1,000,000US.
Personally I think the machine I saw built is a hell of a lot better than the imported ones.
Regards Alan Case