What -I- want to know is this:
If you were to completely surround the world in a spherical piece of bread, would gravity and a sphere's structure hold it floating above the earth's surface? If so, a lot of important questions could be raised, such as:
Would the bread orbit at the same speed as earth? If not, couldn't we harvest the hell outta some energy with it?
How transparent IS bread? Would the world be pretty much black? Could you live on the outside crust of the bread?
Could terrorists begin chewing a hole in the bread to disrupt balance and cause the bread to come crashing down?
What WOULD you do with a moldy piece of bread bigger than the earth itself (HOLY CRAP, ISTVAN, THIS SOUNDS LIKE A JOB FOR THE BLACK HOLE!)
And most importantly, what the hell would you call it, for it most certainly is not a sandwich.