What was the interior of the roll like?
Was the shattery crust smooth all over, or cracked in places? I've seen recipes (dutch tiger bread) that have a mix containing rice flour brushed over the top. It cracks as the roll rises during baking.
It doesn't sound like anything I've ever had/made but more information might help.
It is possible that they were a sort of artisan bread, but the superior steam generated in professional ovens made the crust thinner than you got at home.