Two Columns with Display Suite?
The easiest way would be to override the nd_regions.css file in your theme and put something like the following in it:

.nd-region-header,
.nd-region-footer {
  clear: both;
}
.nd-region-left {
  width: 50%;
  float: left;
}
.nd-region-right {
  width: 50%;
  float: right;
}
.nd-region-middle-wrapper {
  display: none;
}


Simply don't put anything in the DS middle column, manage a gutter and you'll be fine.