How to make borders collapse (on a div)?

Use a simple negative margin rather than using display: table.

Updated in fiddle
JS Fiddle

.container { 
    border-style: solid;
    border-color: red;
    border-width: 1px 0 0 1px;
    display: inline-block;
}
.column { 
    float: left;
    overflow: hidden; 
}
.cell { 
    border: 1px solid red;
    width: 120px;
    height: 20px; 
    margin: -1px 0 0 -1px;
}
.clearfix {
    clear:both;
}