http://www.amazon.com/Brown-Bread-Raisin-oz-Pack/dp/B0000TA3QW
This one looks cool for all kinds of stuff.
http://www.buythecase.net/
Odd, it is always on the shelf in my local commissary (Ft Sill). I haven't looked for it elsewhere seriously, though I browsed a few online purchase sites.
Besides liking the taste, it seems like a practical emergency food - relatively high energy, palatable, keeps well - even when opened it will last a few days with reasonable care which is pretty good for a moist bread.