Thanks Peter - nice looking article.

I've not read the whole article yet (that's for when I have more time), but I wonder how your approach compares with the 'classic' crosstab/pivot table approaches...

http://www.sqlteam.com/item.asp?ItemID=2955

http://weblogs.sqlteam.com/jeffs/archive/2005/05/02/4842.aspx

If anyone has time to evaluate this, I'd be very grateful!