I have had Kaiser rolls many times in Austria and Germany and want to try to make them myself.  The crumb is different than Kaiser rolls I get in the U.S. - it is soft and maybe you could call it fluffy.  It does not have big holes like artisan bread nor does it have small bubbles like most breads.  I would call it almost cottony in appearance.  The flavor of these rolls (usually fresh at breakfast) is wonderful.  I look forward to trips to Austria just for the bread.