Hi CBTENGR
There are mainstay rations available at
http://www.survivorind.com/3600.html
or there is Traditional Scottish Shortbread and Highland Oatcakes available at
http://www.walkersus.com/products/gift-tins-more/03702
or if you want to bake Dundee Cake yourself you can follow the recipe at
http://www.rampantscotland.com/recipes/blrecipe_dundee.htm
Dundee Cake when stored in a tin will last quite a while (up to 6 months if stored correctly in a cool dark place)