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As far as Im aware roco never made anything WW1 although I have seen an A7V done by Viking in 1/87
heres a metel kit for the Burstyn tank:
http://www.doppeladler.com/themodeller/kits/87burstyn.htm
Ah I see what you mean the roco figures are conversions I think and no longer available for many years but its possible to get Prieser figures which are probarbly better....