http://www.reprorations.com/ is apparently moving and will not be accepting orders until September 2015.
Here is someone selling reproduction British WW II rations: http://reprorations.com/Britain%20WW2/WW2-Britain.htm
They also sell reproduction German rations among others: http://reprorations.com/Germany%20WW2/WW2-Germany.htm
France's "reserve rations" for WW I http://17thdivision.tripod.com/rationsoftheageofempire/id15.html
Peanut butter with pickle slices on a burger bun, a ww2 meat substitute it's good!