Any idea what the cab is from? I doubt it was completely made up from scratch. Maybe a Volvo or MAN
According to the info from a Swedish forum there should be an identifying builders plaque or something similar somewhere in the cab, but I haven't been able to find it... Maybe it's missing or just well hidden. If I do find it I'll report back!
I did some digging and you may actually be onto something, look at this Volvo L370 fire truck from 1955 and compare the aluminium side trim and door handles to those on my truck:
