Anyone have a macro that will work for large rowsets?

I found one at http://www.ozgrid.com/VBA/ExcelRanges.htm....which works fine
if I have less than 20k rows. If I have more than that it inserts a lot of
blanks rows, but at the top, instead of at each row change...

But my worksheets routinely have 40k rows. Obviously if I have say 50k rows
and try to add 20k blank rows, well that's more than the 64k that Excel can
handle....in such case I should get a warning popup. Anyone have a way to
check a cloumn for changes and InsertRows en masse (looping through each rows
is so slow...)?

I have a sample file I can foward to anyone that needs it.