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Austria never actually built a tank but they were offered a design in 1911 which predates everything else but remained on paper only, maybe this is the one your refering too....
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....