We purchased this bed, specifically so we could add matching pieces later.  There we too few cross supports, and the photograph on the sale page showed the bed using only one mattress or box spring. In order to have the bed at a decent height, we had to purchase plywood to keep the mattress from sagging between the cross slats.

The end board is extremely thin and bends quite easily.  It is a beautiful bed to look at and with the additional expense for plywood, we are enjoying our new bed.