An empty table data will always display as approx 1 font character high. I think its around 7 pixels. One way around this is to put a 1x1 clear gif in the table data, and use it to specify your table data size. You can then use the bgcolor in the table data to specify color. You dont need to make the clear gif the whole size of the table data, just 1x1 should do it.
This works good to bump out width too.
<tr>
<td bgcolor="red"><img src="clear.gif" height="1" width="1"></td>
</tr>
That should do it for you.
You can also do it with style sheets, but thats a whole other ballgame.
Z~
P.S. I attached a 1 pixel x 1 pixel clear gif, if you need it.