There's such an easy way to do this in native Acrobat. Takes only a few minutes.
With thumbnails showing, select all 7 pages, hold down the Ctrl key, and drag the cursor to after the last page. Now you will have 14 pages (1 thru 7 and 1 thru 7). Repeat with all 14 pages to make 28, repeat with 28 to make 56, 112, 224, and so on. If you create more than 700 pages, delete them.
To make life easy doing this, drag the thumbnail pane wider so that you have 7 pages per row.