For the A7V, there's a Schiffer book (a kind of Squadron Signal 'in action' book from Germany. Also, very good references at:
http://freespace.virgin.net/shermanic.firefly/a7v.html
and:
http://mailer.fsu.edu/~akirk/tanks/pol/polisha7v.html
and:
http://www.wwi-models.org/Photos/Ger/A7V/
Do you have any info (drawings!!!?) of the munition carrier based on the A7V???