Hallo,
habe es hinbekommen.

Code:
.configurator {
  display: table;
}

.option {
   display: table-row;
}


.name {
   display: table-cell;
   vertical-align: top;
   font-weight:bold;
}

.dummy {
   display: table-cell;
   width:20px;
}


.less {
   display: table-cell;
   vertical-align: top;
}

.quantity {
   display: table-cell;
   vertical-align: top;
   text-align:center;
}

.unit {
   display: table-cell;
   vertical-align: top;
   text-align:center;   
}

.more {
   display: table-cell;
   vertical-align: top;
}

.complete {
  margin-top:20px;
}

.complete .name {
  border-bottom: 3px double #000000;
  display:inline;
}

.complete .price {
  border-bottom: 3px double #000000;
}

.complete .unit {
  border-bottom: 3px double #000000;
  display:inline;
}
sind zwar noch paar Sachen mehr aber falls es jemanden interessiert. Das ganze geht mit display: table, table-row, table-cell

Gruß
cdp