I pinned a possible solution made with plumbing pipes ( I would paint them) and wooden planks as "table tops" for the key board and monitor. Very unobtrusive. My desk is not actually the reception desk per se, it is behind the reception desk but easily seen so it cant look cheap or cheesy. So no boxes or books or make shift stuff. It needs to be 15" for the keyboard and slightly higher for the monitor. So the 2 tier one of painted pipes might just work.