Reply To: How would I accomplish this?

Or try playing around with his

#bbpress-forums li.bbp-body ul.forum, #bbpress-forums li.bbp-body ul.topic {
border-top: 1px solid #eee;
overflow: hidden;
padding: 8px;
float: left;
width: 20%;
}

This will give 5 rows, 10 would not fit any screen.
his idea you have might sound good, but it will cause lots of issues on different viewports/mobile