Does anyone make these pre built for the Tamiya WW2 kits?
Yes,I have seen them that way.
Sector35 out of Ukraine used to sell prebuilt metal tracks.
Who made them?
Just go on ebay and search 1/35 assembled metal tracks,a lot are Sector Micro,but there are others too.
I have also seen some people 3D printing fully assembled tracks. (in sections)
Upon opening you flex then to break what tiny connections there are between the individual links and you then have a fully positionable set of tracks for your model.
I have seen such reports. I don’t know if anyone is doing this yet commercially.
I have the Tamiya Kettenrad tracks. Very nice.
Also while not metal or pre built, the easiest tracks I have ever built.