On this Ukrainian page are some excellent scale drawings, toward the bottom (you can click on the bit that says 'blah blah blah 300dpi' to get huge versions):
There are various dimensions tabulated too (although in Ukrainian, it should be possible to figure out what some of the measurements refer to, such as length).
There are doubtless many other useful sites, but that's a good starting point at least for plans.
The first drawing shows the modifications suggested to allow the A7V to carry the standard 77 mm artillery piece, it was also to carry Becker guns in the rear. it was not built becouse it would have thrown the center of gravity forward and increased the nose heavy effect.(Hundleby Strasheim)
The second photo is a A7V design Vollmer was forced into producing when the demand was made for overall 30mm armour Becker guns along with machine guns were to be used. (Same Source)
All the Best
Tim R
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"The life given us by nature is short; but the memory of a well-spent life is eternal" -Cicero 106-43BC
I think they're just early, discarded, designs, part of the process leading to the final A7V. God, they're even more ugly than the A7V, something I never thought possible...
Doggowitz, all the reference books that I have been able to check (which amounts to 2; Hundleby & Strasheim and Mark Whitmore's "Mephisto") have an incorrect illustration of the driver's hatch. Hundleby's illustration is on pages 104 & 105 and Whitmore's illustration is on page 14. There are (or were) 2 different types, one used on early build tanks and one used on later builds. I have drawn up a general view (no measurements) that should indicate what I mean. see attachment.
The photos I have checked are available on the Australian War Memorials website http://www.awm.gov.au and the photo numbers are E02368, E02369, E02459, E02876. Another photo that shows the interior view of the drivers hatch is quoted in Whitmore's book as an Imperial War Museum photo; No. Q55073 (Shown in "Mephisto" on page 35). I have checked the IWM site but have been unable to find this picture. The difference between top and bottom of the hatch is most striking in "Elfriede".
Hope this information is of some use. If I can, I will try to draw up a measured diagram.