Hi, the stuff you should look for is "Blankleder". 
9oz would be 3,6mm. They have proper leather in the thickness from 3,5-4,0mm for about 63€ per square metre, for the best quality, down to 52€ per square metre. They normaly have 4 different qualities. 
They might be a bit pricier compared to the other companies in Germany, but well worth it!! 
I was speaking about these guys http://kobel-leder.de/ 
Cheers, 
Marcel