Here are the links to some interesting videos ... and you can buy them!
German Tank A7V "Elfriede" http://www.criticalpast.com/video/65675028111_French-soldiers_captured-German-tank_soldiers-in-trench_dead-on-stretchers
German Tank A7V "Hagen" http://www.criticalpast.com/video/65675024094_Battle-of-Hindenburg-Line_captured-guns_Canadian-officials-view-captured-artillery_captured-tank
US Mark VIII http://www.criticalpast.com/video/65675048447_Mark-VIII-tank_climbing-test_World-War-I-tanks_Benedict-Crowell
US Ford Tank http://www.criticalpast.com/video/65675023591_Military-tanks-testing_military-officials_cross-railroad-tracks_Tank-knocks-down-posts
British Mark I (Solomon camo!) http://www.criticalpast.com/video/65675028128_Irish-troops_Battle-of-Ancre_soldiers-standing_taking-positions-in-trenches