I hear you about the
'technique', I used it muchly to get gif's and or other content to spread down long columns, but I wasn't that familiar with CSS then.
I also haven't used tables for a while, but I will check - off the top of my head though, can you assign height to the td's? IE., you have three rows, say, then each would be 33%, or 2x25% plus 50%?
Also, can you use a containing div that surrounds the table with a height value on that?

It may take some fancy border and background colouring. Is there a way I could see your pages?