I love your grid. When do you think it will be ready for release? I have a few suggestions if you don't mind.
1) Would it be possible to prevent the vertical scrollbar from expanding all the way to the top of the column header and instead be restricted to the "data" area? I think that it would be more intuitive for users since the headers do not scroll. (This could optionally be turned back to original behavior if some people prefer the current functionality).
2) Would it be possible to have the scrollbar always visible but be grayed out if all the rows fit on the screen? This would be consistent with IE where the scrollbar is always visible on the right side but disabled if you can't scroll. (This could optionally be turned off if some people prefer the current behavior).
The reason why I suggest these changes is that I would like to display a small image at the far right of the headers row that users can click on to refresh the data. This image would have the same width as the scoll bar but it would look funny if the image was present on the grid without the scrollbar. Another example would be a button on the far left of the headers row that would select all rows when clicked.
I can email you a screenshot of an application that has a grid with this functionality if it can help you visialize what I'm talking about.