Thanks Mike. Not having column headers is a no go. And my idea to show all the data in every cell in its own progress bar means the cells themselves won't hold data directly, so it's probably not possible to use Sorting, Ordering, Filtering, all that good stuff.
Did you have another idea for the progress bar as a background for the row?
You brought up a case I hadn't thought of – namely – horizontal scrollbar wouldn't work. What would really be cool is a progress bar bound to the top or bottom of each row, or as a background (with the appropriate color changes to cell content) that is sized to the width of the grid regardless of horizontal scrolling!