Hi Oliver,
Yes there are still some Federal 604 tractors around, we (family) have two in our collection (no trailers yet), one is drivable the other is not.
Both vehicles served in the New Zealand Army during the 1950's, untill they were replaced by International F230D transporters.
There is another Federal 604 about 25 km away in a small muesum, but this to has no trailer and has been coverted into a heavy wrecker!
As far as the trailers go they are now classed as very rare in original condition, because most have been stretched or heavily modified.
I have seen an original trailmobile in New Zealand way back in the late 70's
I thought it had been shortend, but found out later that they are not very big anyway (still trying to track that one down) its probably scrap by now.
There are a some Federal's in Australia that I know of which were for sale a while ago, but don't know about trailers.
Would be interested in any more pictures you may have of these handsome trucks
Kind regards,
Brent Delaney,