Safari Arms LTD (http://safariarms.com/) sells 10.75x68 Mauser ammo for $205.00 - $215.00 per box.

The following companies make brass for the 10.75x68 Mauser. Hornaber, Bertram, Quality Cartridge, Buffalo Arms Co (formed brass, http://www.buffaloarms.com/Search.aspx?TERM=10.75x68

Safari Arms LTD Ammo.
I have an original 1930ish 10.75x68 Mauser. I purchased a box of ammo from Safari Arms LTD and the cartridges will not chamber. I was told that there is a difference is specs between SAAMI and CIP. The Safari Arms LTD is too long for my chamber.

10.75x68 Case Comparison
A Safari Arms LTD cartridge using Hornaber brass, a resized and fired Hornaber case and a resized, shortened and fired Bertram case used for crimping 400 gr Woodleigh bullets (2110 fps).