7068 aluminium alloy plate  is one of the strongest commercially available aluminium alloys plate  , with a tensile strength comparable to that of some steels. 7068-T6511 has typical ultimate tensile strength of 710 MPa (103 ksi) versus a similar product produced from 7075-T6511 that would have a typical ultimate tensile strength of 640 MPa (93 ksi). Typical yield strength for alloy 7068-T6511 is 683 MPa (99.1 ksi) versus 590 MPa (86 ksi) for a similar product produced from 7075-T6511. Strength allowables for this alloy are provided in Metallic Materials Properties Development and Standardization for design..

Aluminium Alloy 7075 offers the highest strength of the common screw machine alloys. The superior stress corrosion resistance of the T173 and T7351 tempers makes alloy 7075 a logical replacement for 2024, 2014 and 2017 in many of the most critical applications. The T6 and T651 tempers have fair machinability. aluminium alloys plate 7075 is heavily utilized by the aircraft and ordnance industries because of its superior strength.

The best way to find an answer for this is to contact a metals supplier for quote on similar bar product. I was going to suggest that you look in the McMaster-Carr online catalog but I looked a moment ago and they have dropped 7068  aluminium alloys plate  in favor of 7050, also a superior aluminum alloy. They still carry 7075 which is somewhat weaker but still better than 6061 aluminium alloys plate and 2024 aluminium alloys plate. You can contact Kaiser-Tennalum to find a distributor for 7068