Ah.. something out of the original sentence should be added which is a little different from the change from #1 to 2: nothing added out of the original sentence.
3. There is about to be a fight in the kitchen. — (X) A fight is about to be in the kitchen.-- Not natural at all.
4. There is bound to be a riot in Dacca. — (X) A riot is bound to be in Dacca.-- Different meaning: focus on where a riot might occur, not if one might occur.