Get a woodworker buddy to cut you a plaque. Bolt the skull cap to the plaque and then remove them. Make up some paper mache (google it) and mound it up until it gives a pleasing shape and allow to dry completely. Go to a fabric store and buy a yard of velvet. Tuck and staple (to the backside) this over the paper mache, BUT BEFORE YOU DO THIS, insert the bolts, as the heads will be covered up by the velvet.